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Eclipse, Java, MySQL

without comments

While I previously blogged about installing Netbeans 8, some of my students would prefer to use the Eclipse IDE. This post shows how to install and configure Eclipse IDE, include the mysql-connector-java.jar, and write Java to access the MySQL.

You can download Eclipse IDE and then open it in Fedora’s Archive Manager. You can use the Archive Manager to Extract the Eclipse IDE to a directory of your choice. I opted to extract it into my student user’s home directory, which is /home/student.

After extracting the Eclipse IDE, you can check the contents of the eclipse directory with the following command:

ls -al eclipse

You should see the following:

drwxrwxr-x.  8 student student   4096 May  8 22:16 .
drwx------. 33 student student   4096 May  8 21:57 ..
-rw-rw-r--.  1 student student 119194 Mar 20 07:10 artifacts.xml
drwxrwxr-x. 11 student student   4096 May  8 22:16 configuration
drwxrwxr-x.  2 student student   4096 Mar 20 07:10 dropins
-rwxr-xr-x.  1 student student  78782 Mar 20 07:08 eclipse
-rw-rw-r--.  1 student student    315 Mar 20 07:10 eclipse.ini
-rw-rw-r--.  1 student student     60 Mar 17 15:11 .eclipseproduct
drwxrwxr-x. 41 student student   4096 Mar 20 07:10 features
-rwxr-xr-x.  1 student student 140566 Mar 20 07:08 icon.xpm
drwxrwxr-x.  4 student student   4096 Mar 20 07:09 p2
drwxrwxr-x. 12 student student  40960 Mar 20 07:10 plugins
drwxrwxr-x.  2 student student   4096 Mar 20 07:10 readme

You can launch the Eclipse IDE with the following command-line from the eclipse directory:

./eclipse &

While you can run this from the /home/student/eclipse directory, it’s best to create an alias for the Eclipse IDE in the student user’s .bashrc file:

# Set alias for Eclipse IDE tool.
alias eclipse="/home/student/eclipse/eclipse"

The next time you start the student user account, you can launch the Eclipse IDE by entering eclipse in the search box opened by clicking on the Activities menu.

The following steps take you through installing Eclipse on Fedora Linux, which is more or less the same as any Linux distribution. It’s very similar on Windows platforms too.

Eclipse Installation

EclipseInstall_01

  1. Navigate to eclipse.org/downloads web page to download the current version of the Eclipse software. Click the Linux 32 Bit or Linux 64 Bit link, as required for your operating system.

  1. Click the Green Arrow to download the Eclipse software.

  1. The next dialog gives you an option to open or save the software. Click the Open with radio button to open the archive file.

  1. This the Linux Archive Manager. Click the Extract button from the menu tab to open the archive file.

  1. This extract button on file chooser dialog to install Eclipse into the /home/student/eclipse directory. Click the Extract button to let the Archive Manager create a copy of those files.

  1. The Archive Manager presents a completion dialog. Click the Close button to close the Archive Manager.

After installing the Eclipse software, you can configure Eclipse. There are sixteen steps to setup the Eclipse product. You can launch the product with the

Eclipse Setup

You need to launch the Eclipse application to perform the following steps. The syntax is the following when you did create the alias mentioned earlier in the blog post:

eclipse &

The following steps cover setting up your workspace, project, and adding the MySQL JDBC Java archive.

  1. The branding dialog may display for 30 or more seconds before the Eclipse software application launches.

  1. The Workspace Launcher opens first on a new installation. You need to designate a starting folder. I’m using /home/student/workspace as my Workspace. Click the OK button when you enter a confirmed workspace.

  1. After setting the Workspace Launcher, you open to the Eclipse Welcome page. Click second of the two icons on the left to open a working Eclipse environment. Alternatively, you can connect to Tutorials on the same page.

  1. From the developer view, click on the File menu option, the New option on the list, and the Java Project option on the floating menu. Eclipse will now create a new Java project.

  1. The New Java Project dialog lets you enter a project name and it also gives you the ability to set some basic configuration details. As a rule, you simply enter the Project Name and accept the defaults before clicking the Finish button.

  1. After creating the new Java project, Eclipse returns you to the Welcome page. Click second of the two icons on the left to open a working Eclipse environment.

  1. Now you should see the working environment. Sometimes it takes the full screen but initially it doesn’t. Navigate to the lower right hand side, and expand the window to full size.

  1. Now you should see the full screen view of the Eclipse working environment.

  1. Now you create a new Java class by navigating to the File menu options, then the New menu option, and finally choosing the Class floating menu.

  1. The New Java Class dialog requires you to provide some information about the Java object you’re creating. The most important thing is the Java class name.

  1. The only difference in this copy of the New Java Class dialog is that I’ve entered HelloWorld as the Java Class’s name. Click the Finish button when you’re done.

  1. Eclipse should show you the following HelloWorld.java file. It’s missing a main() method. Add a static main() method to the HelloWorld.java class source file.

  1. This form shows the changes to the HelloWorld.java file. Specifically, it adds the It’s missing a main() method. Add a static main() method to the HelloWorld.java class source file.

  1. You can click the green arrow from the tool panel or you can click the Run menu option and Run submenu choice to test your program.

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    // Class definition.
    public class HelloWorld {
      public static void main(String args[]) {
        System.out.println("Hello World."); }}

  1. The Save and Launch dialog tells you that you’re ready to test creating a copy of the Java class file. Click the OK button to continue.

  1. The results from your program are written to the Console portion of the Eclipse IDE. This concludes the setup of a workspace, project, and deployment of actual Java classes.

    Hello World.

Add MySQL JDBC Library

The following instructions add the MySQL Library and demonstrate how to write Java programs that connect to the MySQL database. They also use the mysql project.

EclipseMySQLLib_01

  1. Navigate to the Project menu and choose the Properties menu option.

EclipseMySQLLib_02

  1. The Properties menu option opens the Properties for the mysql project on the Order and Export tab. Click the Libraries tab to add an external library.

EclipseMySQLLib_03

  1. In the Libraries tab click the Add Library… button on the right to add an external library.

EclipseMySQLLib_04

  1. In the JAR Selection dialog, click on Computer in the Places list, then click on usr, click on share, and click on java. The Name list should now include mysql-connector-java.jar file, and you should click on it before clicking on the OK button.

EclipseMySQLLib_05

  1. You create new Java class file by clicking on the File menu. Then, you choose the New menu option and the Class menu option from the floating menu.

EclipseMySQLLib_06

  1. Enter MysqlConnector as the name of the new Java class file and click the Finish button to continue.

EclipseMySQLLib_07

  1. Eclipse generates the shell of the MysqlConnector class as shown in the illustration to the left.

EclipseMySQLLib_08

  1. You should replace the MysqlConnector class shell with the code below. Then, click the green arrow or the Run menu and Run menu option to compile and run the new MysqlConnector Java class file.

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    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
     
    public class MysqlConnector extends Object {
      public static void main(String[] args) {
        try {
          /* The newInstance() call is a work around for some
             broken Java implementations. */
          Class.forName("com.mysql.jdbc.Driver").newInstance();
     
          /* Verify the Java class path. */
          System.out.println("====================");
          System.out.println("CLASSPATH [" + System.getProperty("java.class.path") + "]");
          System.out.println("====================");
     
        } catch (Exception e) {}
        finally {
          /* Verify the Java class path. */
          System.out.println("====================");
          System.out.println("CLASSPATH [" + System.getProperty("java.class.path") + "]");
          System.out.println("====================");
        }
      }
    }

EclipseMySQLLib_09

  1. The Save and Launch dialog informs you are saving a MysqlConnector.java file to your mysql project. Click the OK button to continue.

EclipseMySQLLib_10

  1. The next screen shows that the program successfully connected to the MySQL database by printing the following information to the Console output tab.

    ====================
    CLASSPATH [/home/student/Code/workspace/MySQL/bin:/usr/share/java/mysql-connector-java.jar]
    ====================
    ====================
    CLASSPATH [/home/student/Code/workspace/MySQL/bin:/usr/share/java/mysql-connector-java.jar]
    ====================

EclipseMySQLLib_11

  1. Instead of repeating steps #5 through #10, the image displays the testing of the MysqlResults class file. The code follows below:

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    /* Import the java.sql.* package. */
    import java.sql.*;
     
    /* You can't include the following on Linux without raising an exception. */
    // import com.mysql.jdbc.Driver;
     
    public class MySQLResult {
      public MySQLResult() {
        /* Declare variables that require explicit assignments because
           they're addressed in the finally block. */
        Connection conn = null;
        Statement stmt = null;
        ResultSet rset = null;
     
        /* Declare other variables. */
        String url;
        String username = "student";
        String password = "student";
        String database = "studentdb";
        String hostname = "localhost";
        String port = "3306";
        String sql;
     
        /* Attempt a connection. */
        try {
          // Set URL.
          url = "jdbc:mysql://" + hostname + ":" + port + "/" + database;
     
          // Create instance of MySQL.
          Class.forName ("com.mysql.jdbc.Driver").newInstance();
          conn = DriverManager.getConnection (url, username, password);
     
          // Query the version of the database, relies on *_ri2.sql scripts.
          sql = "SELECT i.item_title, ra.rating FROM item i INNER JOIN rating_agency ra ON i.item_rating_id = ra.rating_agency_id";
          stmt = conn.createStatement();
          rset = stmt.executeQuery(sql);
     
          System.out.println ("Database connection established");
     
          // Read row returns for one column.
          while (rset.next()) {
            System.out.println(rset.getString(1) + ", " + rset.getString(2)); }
     
        }
        catch (SQLException e) {
          System.err.println ("Cannot connect to database server (SQLException):");
          System.out.println(e.getMessage());
        }
        catch (ClassNotFoundException e) {
          System.err.println ("Cannot connect to database server (ClassNotFoundException)");
          System.out.println(e.getMessage());
        }
        catch (InstantiationException e) {
          System.err.println ("Cannot connect to database server (InstantiationException)");
          System.out.println(e.getMessage());
        }
        catch (IllegalAccessException e) {
          System.err.println ("Cannot connect to database server (IllegalAccesException)");
          System.out.println(e.getMessage());
        }
        finally {
          if (conn != null) {
            try {
              rset.close();
              stmt.close();
              conn.close();
              System.out.println ("Database connection terminated");
            }
            catch (Exception e) { /* ignore close errors */ }
          }
        }
      }
      /* Unit test. */
      public static void main(String args[]) {
        new MySQLResult(); }
    }

    After you click the green arrow or the Run menu and Run menu option to compile and run the program, you should see the following output. That is if you’re using my create_mysql_store_ri2.sql and seed_mysql_store_ri2.sql files.

    Database connection established
    I Remember Mama, NR
    Tora! Tora! Tora!, G
    A Man for All Seasons, G
    Around the World in 80 Days, G
    Camelot, G
    Christmas Carol, G
    I Remember Mama, G
    The Hunt for Red October, PG
    Star Wars I, PG
    Star Wars II, PG
    Star Wars II, PG
    The Chronicles of Narnia, PG
    Beau Geste, PG
    Hook, PG
    Harry Potter and the Sorcerer's Stone, PG
    Scrooge, PG
    Harry Potter and the Sorcer's Stone, PG
    Harry Potter and the Sorcer's Stone, PG
    Harry Potter and the Chamber of Secrets, PG
    Harry Potter and the Chamber of Secrets, PG
    Harry Potter and the Prisoner of Azkaban, PG
    Harry Potter and the Prisoner of Azkaban, PG
    Harry Potter and the Half Blood Prince, PG
    Star Wars III, PG-13
    Casino Royale, PG-13
    Casino Royale, PG-13
    Die Another Day, PG-13
    Die Another Day, PG-13
    Die Another Day, PG-13
    Golden Eye, PG-13
    Golden Eye, PG-13
    Tomorrow Never Dies, PG-13
    Tomorrow Never Dies, PG-13
    The World Is Not Enough, PG-13
    Clear and Present Danger, PG-13
    Clear and Present Danger, PG-13
    Harry Potter and the Goblet of Fire, PG-13
    Harry Potter and the Goblet of Fire, PG-13
    Harry Potter and the Goblet of Fire, PG-13
    Harry Potter and the Order of the Phoenix, PG-13
    Harry Potter and the Deathly Hallows, Part 1, PG-13
    Harry Potter and the Deathly Hallows, Part 2, PG-13
    Brave Heart, R
    The Chronicles of Narnia, E
    MarioKart, E
    Need for Speed, E
    Cars, E
    RoboCop, M
    Pirates of the Caribbean, T
    Splinter Cell, T
    The DaVinci Code, T
    Database connection terminated

As always, I hope the note helps those trying to work with the Eclipse product.

Written by maclochlainn

May 10th, 2015 at 2:09 am

C Shared Libraries

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I wrote a shared C library example to demonstrate external procedures in the Oracle Database 11g PL/SQL Programming book. I also reused the same example to demonstrate Oracle’s external procedures in the Oracle Database 12c PL/SQL Advanced Programming Techniques book last year. The example uses a C Shared Library but a PL/SQL wrapper and PL/SQL test case.

One of my students asked me to simplify the unit test case example by writing the complete unit test in the C Progamming Language. The student request seemed like a good idea, and while poking around on the web it appears there’s a strong case for a set of simple shared C library examples. This blog post isn’t meant to replace the C Programming web site and C Programming Tutorial web site, which I recommend as a great reference point.

Like most things, the best place to start is with basics of C programming because some readers may be very new to C programming. I’ll start with basic standalone programs and how to use the gcc compiler before showing you how to use shared C libraries.

The most basic program is a hello.c program that serves as a “Hello World!” program:

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#include <stdio.h>
 
int main() {
  printf("Hello World!\n");
  return(0); }

Assuming you put the C source files in a src subdirectory and the executable files in a bin subdirectory. You compile the program with the gcc program from the parent directory of the src and bin subdirectories, as follows:

gcc -o bin/hello src/hello.c

Then, you execute the hello executable program from the parent directory as follows:

bin/hello

It prints:

Hello World!

You can modify the basic Hello World! program to accept a single input word, like this hello_whom.c program:

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#include <stdio.h>
 
/* The executable main method. */
int main() {
  // Declare a character array to hold an input value.
  char whom[30];
 
  /* Print a question and read a string input. */
  printf("Who are you? ");
  scanf("%s", whom);
  printf("Hello %s!\n", whom);
  return(0); }

You can compile the hello_whom.c program as follows:

gcc -o bin/hello_whom src/hello_whom.c

Then, you execute the hello_whom executable program from the parent directory as follows:

bin/hello_whom
Who are you? Stuart

It prints:

Hello Stuart!

Alternatively, you can modify the hello_whom.c program to accept a stream of text, like the following hello_string.c program:

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#include <stdio.h>
 
/* The executable main method. */
int main() {
  // Declare a character array to hold an input name.
  char phrase[4000];
 
  /* Print a question and read a string input. */
  printf("Hello? ");
  scanf("%[^\n]%*c", phrase);
  printf("Hello %s!\n", phrase);
  return(0); }

The [] is the scan set character. The [^\n] on line 10 defines the input as not a newline with a white space, and the %*c reads the newline character from the input buffer. After you compile the program you can call it like this:

bin/hello_string
Hello? there, it reads like a C++ stream

It would print:

Hello there, it reads like a C++ stream!

These example, like the previous examples, assume the source files are in a src subdirectory and the executable files are in the bin subdirectory. All compilation commands are run from the parent directory of the src and bin subdirectories.

The first example puts everything into a single writingstr.c file. It defines a writestr() function prototype before the main() function and the writestr() function after the main() function.

The code follows below:

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#include <stdio.h>
 
/* Declare two integer variables. */
char path[255], message[4000];
 
/* Define a prototype for the writestr() function. */
void writestr(char *path, char *message);
 
/* The executable main method. */
int main() {
  printf("Enter file name and message: ");
  scanf("%s %[^\n]%*c", &path, &message);
  printf("File name:    %s\n", path);
  printf("File content: %s\n", message);
  writestr(path, message);
  //writestr("/home/student/Code/c/trylib/libfile/test.txt", "A string.");
  return(0); }
 
void writestr(char *path, char *message) {
  FILE *file_name;
  file_name = fopen(path,"w");
  fprintf(file_name,"%s\n",message);
  fclose(file_name); }

You can compile the writingstr.c function with the following syntax:

gcc -o bin/writingstr src/writingstr.c

You can run the writingstr executable file with the following syntax:

bin/writingstr
Enter file name and message: /home/student/Code/c/test.txt A string for a file.
File name:    /home/student/Code/c/test.txt
File content: A string for a file.

You’ll find a test.txt file written to the /home/student/Code/C directory. The file contains only the single sentence fragment entered above.

Now, let’s create a writestr.h header file, a writestr.c shared object file, and a main.c testing file. You should note a pattern between the self-contained code and the approach for using shared libraries. The prototype of the writestr() function becomes the definition of the writestr.h file, and the implementation of the writestr() function becomes the writestr.so shared library.

The main.c file contains the only the main() function from the writingstr.c file. The main() function uses the standard scanf() function to read a fully qualified file name (also known as a path) as a string and then a text stream for the content of the file.

You define the writestr.h header file as:

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#ifndef writestr_h__
#define writestr_h__
 
extern void writestr(char *path, char *message);
 
#endif

You define the writestr.c shared library, which differs from the example in the book. The difference is the #include statement of the writestr.h header file. The source code follows:

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#include <stdio.h>
#include "writestr.h"
 
void writestr(char *path, char *message) {
  FILE *file_name;
  file_name = fopen(path,"w");
  fprintf(file_name,"%s\n",message);
  fclose(file_name); }

You define the main.c testing program as:

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#include <stdio.h>
#include "writestr.h"
 
/* Declare two integer variables. */
char path[255], message[4000];
 
/* The executable main method. */
int main() {
  printf("Enter file name and message: ");
  scanf("%s %[^\n]%*c", &path, &message);
  writestr(path, message);
  return(0); }

Before you begin the process to compile these, you should create an environment file that sets the $LD_LIBRARY_PATH environment variable or add it to your .bashrc file. You should point the $LD_LIBRARY_PATH variable to the directory where you’ve put your shared libraries.

# Set the LD_LIBRARY_PATH environment variable.
export LD_LIBRARY_PATH=/home/student/Code/c/trylib/libfile

With programs defined, you need to first compile the writestr.c shared library first. You use the following syntax from the parent directory of the src and bin subdirectories.

gcc -shared -fPIC -o bin/writestr.so src/writestr.c

If you haven’t set the $LD_LIBRARY_PATH, you may raise an exception. There’s also an alternative to setting the $LD_LIBRARY_PATH before you call the gcc executable. You can use the -L option set the $LD_LIBRARY_PATH for a given all to the gcc executable, like:

gcc -L /home/student/Code/c/trylib/libfile -shared -fPIC -o bin/writestr.so src/writestr.c

Then, you compile the main.c program. You must put the writestr.so shared library before you designate the main target object and main.c source files, like this:

gcc bin/writestr.so -o bin/main src/main.c

Now, you can perform a C-only unit test case by calling the main executable. However, you must have set the $LD_LIBRARY_PATH environment variable at runtime too. You see the following reply to the “Enter file name and message” question when you run the main program unit:

bin/main
Enter file name and message: /home/student/Code/c/trylib/libfile/test.txt A long native string is the second input to this C program.

You can now see that the a new test.txt file has been written to the target directory, and that it contains the following string:

A long native string is the second input to this C program.

As always, I hope this helps those you want to write shared libraries in the C programming language.

Written by maclochlainn

May 7th, 2015 at 1:46 am

Leaf node queries

without comments

A reader posted A dynamic level limiting hierarchical query about Oracle’s hierarchical queries. They wanted to know how to capture only the hierarchy to the level where the first leaf node occurs. They gave me the following hierarchy map as an example:

               1                                    2
        +-------------+                       +-----------+
        |             |                       |           |      
        3             5                       4           6
    +---------+    +-----------+           +-----+    +------+
    |         |    |           |           |     |    |      |
    7         9    11          13          8     10   12     14
+-----+   +-----+  +--+    +-------+                       +-----+ 
|     |   |     |     |    |       |                       |     |
15    17  19    21    23   27      29                     16     18
                                                                 +---+
                                                                     |
                                                                     20

You can find the node values and hierarchical level with the following query:

SELECT   tt.child_id
,        LEVEL
FROM     test_temp tt
WHERE    CONNECT_BY_ISLEAF  = 1
START
WITH     tt.parent_id IS NULL 
CONNECT
BY PRIOR tt.child_id = tt.parent_id
ORDER BY 2;

We really don’t need the node values to solve the problem. We only need the lowest LEVEL value returned by the query, which is 3. The combination of the MIN and CONNECT_BY_ISLEAF functions let us solve this problem without writing a PL/SQL solution. The subquery returns the lowest level value, which is the first level where a leaf node occurs.

SELECT   LPAD(' ', 2*(LEVEL - 1)) || tt.child_id AS child_id
FROM     test_temp tt
WHERE    LEVEL <= (SELECT   MIN(LEVEL)
                   FROM     test_temp tt
                   WHERE    CONNECT_BY_ISLEAF  = 1
                   START
                   WITH     tt.parent_id IS NULL 
                   CONNECT
                   BY PRIOR tt.child_id = tt.parent_id)
START
WITH     tt.parent_id IS NULL
CONNECT
BY PRIOR tt.child_id = tt.parent_id;

It returns:

               1                                    2
        +-------------+                       +-----------+
        |             |                       |           |      
        3             5                       4           6
    +---------+    +-----------+           +-----+    +------+
    |         |    |           |           |     |    |      |
    7         9    11          13          8     10   12     14

While I answered the question in a comment originally, it seemed an important trick that should be shared in its own post.

Written by maclochlainn

April 30th, 2015 at 4:31 pm

Netbeans 8 – Fedora

with 3 comments

Some of my students want to use the Fedora image that I built for my database classes in my Java software development life cycle course. As a result, they wanted a Java development environment installed. I examined JDeveloper 11g (11.1.1.7.0) and 12c (12.1.3) but resolved on the more generic Netbeans 8 (8.0.2) IDE.

JDK 7 with Netbeans 8 Download

You can download the generic Netbeans 8 IDE, the JDK 7 with Netbeans, or the JDK 8 with Netbeans for the Linux installation. After you download the executable program, you should follow these instructions to install the Netbeans 8 IDE on Fedora.

As the student user, you can download the file to your ~student/Downloads directory and then run these two commands:

chmod +x ./jdk-7u80-nb-8_0_2-linux-x64.sh
sudo ./jdk-7u80-nb-8_0_2-linux-x64.sh

It produces the following output log:

Configuring the installer...
Searching for JVM on the system...
Preparing bundled JVM ...
Extracting installation data...
Running the installer wizard...

Then, it launches the installer. These screens show you how to install and create your first Java project.

JDK 7 with Netbeans 8 Installation

JDK7Netbeans8_01

  1. The first installation dialog welcomes you to the JDK 7 Update and NetBeans 8 Installer. Click the Next button to proceed.

JDK7Netbeans8_02

  1. The second installation dialog asks you to accept the terms in the license agreement. Click the Next button to proceed.

JDK7Netbeans8_03

  1. The third installation dialog asks you to install Netbeans 8. Click the Browse button if you would like to install it in a different area. Click the Next button to proceed.

JDK7Netbeans8_04

  1. The fourth installation dialog asks you to install another Java JDK 7 that supports the current release of Netbeans 8. Click the Browse button if you would like to install it in a different area. Click the Next button to proceed.

JDK7Netbeans8_05

  1. The fifth installation dialog shows you the progress bar for installing Java JDK 7 that supports the current release of Netbeans 8. You may not need to click the Next button to proceed because it should progress to the Netbeans progress dialog. Click the Next button to proceed when it doesn’t do it automatically.

JDK7Netbeans8_06

  1. The sixth installation dialog shows you the progress bar for installing Netbeans 8. Click the Next button to proceed when it doesn’t do it automatically.

JDK7Netbeans8_08

  1. The next screen is the final screen of the Java SE Development Kit and NetBeans IDE Installer. Click the Finish button to complete the installation.

After the installation, you need to check if the netbeans program can be found by users. It shouldn’t be found at this point because it isn’t in the default $PATH environment variable.

Configuring the student user

You can set the $PATH variable dynamically like this:

export PATH=$PATH:/usr/local/netbeans-8.0.2/bin

The netbeans program location was set in Step #4 of the Netbeans installation. After setting the $PATH environment variable, you can run netbeans with this syntax:

./netbeans &

However, the better approach is to put the following lines in your .bashrc file. This change ensures that you can access the netbeans program anytime you launch a Terminal session.

# Add netbeans to the user's PATH variable.
export PATH=$PATH:/usr/local/netbeans-8.0.2/bin

After you have configured the student user’s .bashrc file, you can now use Netbeans to create a Java project.

Create a new Netbeans project

JDK7Netbeans8_07

  1. The next screen is the Netbeans 8 Start Page. This is where you can create your first Java development project.

JDK7Netbeans8_09

  1. You click the File menu and then the New Project menu option to open a new project.

JDK7Netbeans8_10

  1. It launches the New Project dialog at Step #1 – Choose Project, where you choose Java from your Categories list and Java Application from the Projects list. You click the Next button to continue.

JDK7Netbeans8_11

  1. It launches the New Project dialog at Step #2 – Name and Location, where you enter a Project Name. The example uses MySQLJava as the project name. You click the Next button to continue.

JDK7Netbeans8_12

  1. It launches the MySQLJava.java tab in the Netbeans 8 application. This is where you can enter your code.

After you successfully download the Java 7 SE and Netbeans 8, you should download JDK 8 with Netbeans 8 because Java 7 EOL (End-of-Life) is April 30th, 2015. You may think that you need to uninstall the JDK 7 with Netbeans 8 before you install the JDK 8 with Netbeans 8, but you don’t have to do so. When you install JDK 8 with Netbeans 8 into an environment with a preinstalled JDK 7 with Netbeans 8, the installer only adds the JDK 8.

The following segments of the post show you how to download and install JDK 8 with Netbeans 8, and how to configure Netbeans to work with the JDK 7 and JDK 8 as interchangeable libraries.

JDK 8 with Netbeans 8 Download

You can now download the JDK 8 with Netbeans for the Linux installation. After you download the executable program, you should follow these instructions to install it on Fedora.

As the student user, you can download the file to your ~student/Downloads directory and then run these two commands:

chmod +x ./jdk-8u45-nb-8_0_2-linux-x64.sh
sudo ./jdk-8u45-nb-8_0_2-linux-x64.sh

It produces the following output log:

Configuring the installer...
Searching for JVM on the system...
Preparing bundled JVM ...
Extracting installation data...
Running the installer wizard...

Then, it launches the installer, which will be very similar to the steps you went through earlier. There are differences. There are only five screens that you navigate as opposed to the seven from the earlier JDK 7 with Netbeans 8 installation, as you’ll see below.

JDK 8 with Netbeans 8 Installation

JDK8Netbeans_01

  1. The first installation dialog welcomes you to the JDK 8 Update and NetBeans 8 Installer. Click the Next button to proceed.

JDK8Netbeans_02

  1. The second installation dialog installs the JDK 8. Click the Next button to proceed.

JDK8Netbeans_03

  1. The third installation dialog is a summary of what you’ll install. Click the Install button to proceed.

JDK8Netbeans_04

  1. The fourth installation dialog shows you a progress bar. You don’t need to do anything but watch the progress.

JDK8Netbeans_05

  1. The fifth installation dialog shows you the installation is complete. Click the Finish button to proceed when it doesn’t do it automatically.

After you have installed the JDK 8 SE, you can use Netbeans to add the JDK 8 platform.

Add the JDK 8 Platform to Netbeans 8

JDK8Platform_01

  1. After you open Netbeans 8, you choose the Tools menu choice. Then, you select the Java Platforms menu option.

JDK8Platform_02

  1. It launches the Java Platform Manager dialog. You click the Add Platform button to add the JDK 8 platform.

JDK8Platform_03

  1. It launches the Add Java Platform dialog. Leave the Java Standard Edition radio button checked. You click the Next button to proceed.

JDK8Platform_04

  1. It launches the Add Java Platform file chooser dialog. Here you navigate to find the JDK 8 software, which is located in /usr/local/jdk1.8.0_45 directory.

JDK8Platform_05

  1. After selecting the /usr/local/jdk1.8.0_45 directory as the platform folder, click the Next button to proceed.

JDK8Platform_06

  1. After setting the directory, you’re asked to verify the Java Platform information. If it’s correct, click the Finish button to proceed.

JDK8Platform_07

  1. After finishing the installation, you’ll see that you have two installed Java Platforms. Unfortunately, the first one installed is the default unless you modify the netbeans.conf file. You click the Close button to complete the process.

Set JDK 8 Platform as the Default Java Platform for Netbeans 8

After adding the JDK 8 Java Platform, you can change the default setting my manually editing the /usr/local/netbeans-8.0.2/etc/netbeans.conf file. You simply remark out the line for JDK 7 and replace it with one for JDK 8, as shown below. The next time you boot the Netbeans application it uses Java 1.8.

# netbeans_jdkhome="/usr/local/jdk1.7.0_80"
netbeans_jdkhome="/usr/local/jdk1.8.0_45"

The next time you launch Netbeans 8, it will use JDK 8 because you set that as the default Java Platform

As always, I hope this helps those looking for information like this.

Written by maclochlainn

April 29th, 2015 at 1:32 am

SQL Developer – Fedora

with 3 comments

This is the continuation of my efforts to stage an awesome Fedora developer’s instance. It shows you how to install Java 1.8 software development kit, which is nice to have. Though you can’t use Java 1.8 officially with Oracle SQL Developer 4.0.3 it is required for Oracle SQL Developer 4.1. Fortunately, the Oracle Product Manager, Jeff Smith has advised us that you can use Java 1.8 JDK with Oracle SQL Developer 4.0.3, and he’s written a comment to the blog post that it runs better with the Java 1.8 SDK.

After you install Oracle SQL Developer 4.0.3 or Oracle SQL Developer 4.1, you can watch Jeff Smith’s YouTube Video on SQL Developer 3.1 to learn how to use the basics of SQL Developer. I couldn’t find an updated version of the video for SQL Developer 4 but I didn’t try too hard.

You use yum as the root user to install Java SDK 1.8, much like my earlier Installing the Java SDK 1.7 and Java-MySQL Sample Program. The following command installs Java 8:

yum install -y java-1.8*

It produces the following output:

Loaded plugins: langpacks, refresh-packagekit
fedora/20/x86_64/metalink                                   |  18 kB  00:00     
mysql-connectors-community                                  | 2.5 kB  00:00     
mysql-tools-community                                       | 2.5 kB  00:00     
mysql56-community                                           | 2.5 kB  00:00     
pgdg93                                                      | 3.6 kB  00:00     
updates/20/x86_64/metalink                                  |  16 kB  00:00     
updates                                                     | 4.9 kB  00:00     
(1/2): mysql-tools-community/20/x86_64/primary_db           |  21 kB  00:00     
(2/2): updates/20/x86_64/primary_db                         |  13 MB  00:09     
updates/20/x86_64/pkgtags
updates
(1/2): updates/20/x86_64/pkgtags                            | 1.4 MB  00:02     
(2/2): updates/20/x86_64/updateinfo                         | 1.9 MB  00:04     
Package 1:java-1.8.0-openjdk-headless-1.8.0.31-1.b13.fc20.x86_64 already installed and latest version
Package 1:java-1.8.0-openjdk-javadoc-1.8.0.31-1.b13.fc20.noarch already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package java-1.8.0-openjdk.x86_64 1:1.8.0.31-1.b13.fc20 will be installed
---> Package java-1.8.0-openjdk-accessibility.x86_64 1:1.8.0.31-1.b13.fc20 will be installed
---> Package java-1.8.0-openjdk-demo.x86_64 1:1.8.0.31-1.b13.fc20 will be installed
---> Package java-1.8.0-openjdk-devel.x86_64 1:1.8.0.31-1.b13.fc20 will be installed
---> Package java-1.8.0-openjdk-src.x86_64 1:1.8.0.31-1.b13.fc20 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
================================================================================
 Package                          Arch   Version                  Repository
                                                                           Size
================================================================================
Installing:
 java-1.8.0-openjdk               x86_64 1:1.8.0.31-1.b13.fc20    updates 201 k
 java-1.8.0-openjdk-accessibility x86_64 1:1.8.0.31-1.b13.fc20    updates  12 k
 java-1.8.0-openjdk-demo          x86_64 1:1.8.0.31-1.b13.fc20    updates 1.9 M
 java-1.8.0-openjdk-devel         x86_64 1:1.8.0.31-1.b13.fc20    updates 9.2 M
 java-1.8.0-openjdk-src           x86_64 1:1.8.0.31-1.b13.fc20    updates  45 M
 
Transaction Summary
================================================================================
Install  5 Packages
 
Total download size: 56 M
Installed size: 92 M
Downloading packages:
(1/5): java-1.8.0-openjdk-accessibility-1.8.0.31-1.b13.fc20 |  12 kB  00:00     
(2/5): java-1.8.0-openjdk-1.8.0.31-1.b13.fc20.x86_64.rpm    | 201 kB  00:02     
(3/5): java-1.8.0-openjdk-demo-1.8.0.31-1.b13.fc20.x86_64.r | 1.9 MB  00:03     
(4/5): java-1.8.0-openjdk-devel-1.8.0.31-1.b13.fc20.x86_64. | 9.2 MB  00:07     
(5/5): java-1.8.0-openjdk-src-1.8.0.31-1.b13.fc20.x86_64.rp |  45 MB  05:05     
--------------------------------------------------------------------------------
Total                                              187 kB/s |  56 MB  05:05     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction (shutdown inhibited)
  Installing : 1:java-1.8.0-openjdk-1.8.0.31-1.b13.fc20.x86_64              1/5 
  Installing : 1:java-1.8.0-openjdk-devel-1.8.0.31-1.b13.fc20.x86_64        2/5 
  Installing : 1:java-1.8.0-openjdk-demo-1.8.0.31-1.b13.fc20.x86_64         3/5 
  Installing : 1:java-1.8.0-openjdk-accessibility-1.8.0.31-1.b13.fc20.x86   4/5 
  Installing : 1:java-1.8.0-openjdk-src-1.8.0.31-1.b13.fc20.x86_64          5/5 
  Verifying  : 1:java-1.8.0-openjdk-devel-1.8.0.31-1.b13.fc20.x86_64        1/5 
  Verifying  : 1:java-1.8.0-openjdk-demo-1.8.0.31-1.b13.fc20.x86_64         2/5 
  Verifying  : 1:java-1.8.0-openjdk-1.8.0.31-1.b13.fc20.x86_64              3/5 
  Verifying  : 1:java-1.8.0-openjdk-accessibility-1.8.0.31-1.b13.fc20.x86   4/5 
  Verifying  : 1:java-1.8.0-openjdk-src-1.8.0.31-1.b13.fc20.x86_64          5/5 
 
Installed:
  java-1.8.0-openjdk.x86_64 1:1.8.0.31-1.b13.fc20                               
  java-1.8.0-openjdk-accessibility.x86_64 1:1.8.0.31-1.b13.fc20                 
  java-1.8.0-openjdk-demo.x86_64 1:1.8.0.31-1.b13.fc20                          
  java-1.8.0-openjdk-devel.x86_64 1:1.8.0.31-1.b13.fc20                         
  java-1.8.0-openjdk-src.x86_64 1:1.8.0.31-1.b13.fc20                           
 
Complete!

Then, you go to Oracle’s SQL Developer 4.0.3 web page or Oracle’s Beta SQL Developer 4.1 web page and download the SQL Developer RPM. At the time of writing, you download the following SQL Developer 4.0.3 RPM:

sqldeveloper-4.0.3.16.84-1.noarch.rpm

Assuming you download the sqldeveloper-4.0.3.16.84-1.noarch.rpm file to the student user’s account. It will download into the /home/student/Downloads directory. You run the SQL Developer RPM file with the following syntax as the root user:

rpm -Uhv /home/student/Downloads/sqldeveloper-4.0.3.16.84-1.noarch.rpm

Running the SQL Developer RPM produces the following output:

Preparing...                          ################################# [100%]
Updating / installing...
   1:sqldeveloper-4.0.3.16.84-1       ################################# [100%]

You can now run the sqldeveloper.sh file as the root user with the following syntax:

/opt/sqldeveloper/sqldeveloper.sh

At this point, it’s important to note that my download from the Oracle SQL Developer 4.1 page turned out to be SQL Developer 4.0.3. It prompts you for the correct Java JDK, as shown below. You may opt to enter the path to the Java JDK 1.8 for SQL Developer 4.1 because until today you downloaded the Oracle SQL Developer 4.0.3 version from the Oracle SQL Developer 4.1 page. Naturally, the Oracle SQL Developer 4.1 instructions say to use the Java 1.8 JDK on the RPM for Linux Installation Notes web page, as shown below:

SQLDevRPMLinuxNotes

If you assume from the instructions on the Oracle instruction page above that Oracle SQL Developer 4.0.3 and Oracle SQL Developer 4.1 support Java 1.8 JDK, you may enter the location for the Java JDK 1.8 when prompted. Jeff Smith, the Product Manager wrote this blog post on Oracle SQL Developer 4: Windows and the JDK. Unfortunately, you’ll see the following message if you attempt to run Oracle SQL Developer 4.0.3 with the Java 1.8 SDK at the command-line:

 Oracle SQL Developer
 Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
 
Type the full pathname of a JDK installation (or Ctrl-C to quit), the path will be stored in /root/.sqldeveloper/4.0.0/product.conf
/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.31.x86_64
OpenJDK 64-Bit Server VM warning: ignoring option MaxPermSize=256M; support was removed in 8.0

It also raises the following error message dialog:

SQLDev_JVMErrorMsg

Text version of Unsupported JDK Version error message:

You are attempting to run with Java 1.8.0_31.

Running this product is supported with a minimum Java version of 1.7.0_51 and a maximum version less than 1.8.

Update the SetJavaHome in “/root/.sqldeveloper/4.0.0/product.conf” to point to another Java.

This produce will not be supported, and may not run correctly if you proceed. Continue anyway?

The error dialog message tells us that the instructions on the RPM for Linux Installation Notes web page can be misleading. You really need to use the Java JDK 1.7 to be supported officially, but you can safely ignore the error.

If you want a certified component, leave the “Skip This Message Next Time” checkbox unchecked and click the “No” button to continue. At this point, there’s no automatic recovery. You need to open the following file:

/root/.sqldeveloper/4.0.0/product.conf

You need to change the SetJavaHome parameter in the file to the following:

# SetJavaHome /path/jdk
SetJavaHome /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.79-2.5.5.0.fc20.x86_64

After making the change, you can re-run the sqldeveloper.sh shell as follows:

/opt/sqldeveloper/sqldeveloper.sh

It launches the following dialog message:

SQLDeveloperInstall01

The installation pauses to ask you if you want to transfer an existing SQL Developer configuration by raising the following dialog. Assuming this is a new installation, the installer won’t find a prior configuration file. You need to click the “No” button to proceed.

SQLDevInstallPreferences

The installation continues and launches SQL Developer. The first time launch shows you the following Oracle Usage Tracking dialog. If you don’t want your use monitored, uncheck the “Allow automated usage reporting to Oracle” checkbox. Click the “OK” button to continue.

SQLDevUsageTracking

After dismissing the Oracle Usage Tracking dialog, you see the SQL Developer environment:

SQLDeveloper

After installing SQL Developer in the root account, you can install it as the student user. You use this command as the student user:

/opt/sqldeveloper/sqldeveloper.sh

It returns the following error because it’s the second installation and SQL Developer doesn’t prompt you to configure the user’s product.conf file with the working JDK location:

 Oracle SQL Developer
 Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
 
Type the full pathname of a JDK installation (or Ctrl-C to quit), the path will be stored in /home/student/.sqldeveloper/4.0.0/product.conf
Error:  Unable to get APP_JAVA_HOME input from stdin after 10 tries

You need to edit the /home/student/.sqldeveloper/4.0.0/product.conf file, and add the following line to the file:

# SetJavaHome /path/jdk
SetJavaHome /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.79-2.5.5.0.fc20.x86_64

Now, you can launch SQL Developer with the following command:

/opt/sqldeveloper/sqldeveloper.sh

Alternatively, you can add the following alias to the student user’s .bashrc file:

# Set alias for SQL Developer tool.
alias sqldeveloper="/opt/sqldeveloper/sqldeveloper.sh"

You can now launch the SQL Developer tool, like this as the student user:

sqldeveloper

You see the following when SQL Developer launches:

SQLDevInterface

As always, I hope this helps those trying to sort out installing SQL Developer on a Fedora server.

Written by maclochlainn

April 25th, 2015 at 2:38 am

MySQL OCP Exams

with 6 comments

Planning out my year, I decided to take the Oracle OCP and MySQL OCP exams. I checked for review books and was pleasantly surprised to find the soon to be released OCP MySQL Database Administrator Exam Guide (Exam 1Z0-883). However, I noticed that the book was actually prepared for the obsolete and discountinued Exams 1Z0-870, 1Z0-873, and 1Z0-874. As it turns out, Steve O’Hearn has informed me that there isn’t a book and that the posting in Amazon.com is in error.

There isn’t an alternative review book for the OCP MySQL 5.6 Developer or Database Administrator Exams. The question that I have is simple: “How relevant is this book because it was prepared for the older exams?” There isn’t a table of content published on the Amazon.com site. If there was a table of contents it could help me determine how close the book’s content is to the new exam.

As a preparation to figure out the value of the book as a study guide, I’ve reviewed the current Oracle MySQL Training Objectives (listed below). The new MySQL OCP Developer and Administrator exams have the following descriptions and objectives:

  • MySQL 5.6 Developer 1Z0-882. Oracle provides the following outline for their MySQL for Developer (Ed 3) training course:

    Course Objectives

    • Describe the MySQL client/server architecture
    • Use MySQL client programs and common options
    • Program MySQL applications with Java and PHP connectors
    • Use a “NoSQL” approach to store and retrieve data
    • Design efficient tables
    • Create and delete database objects
    • Use expressions in SQL statements
    • Examine database metadata
    • Use SQL statements to modify table data
    • Maintain database integrity with transactions
    • Write multiple table queries
    • Create “virtual tables” containing specific data
    • Create user-defined variables, prepared statements, and stored routines
    • Create and manage triggers
    • Identify and deal with errors and exceptions in client programs
    • Write queries that are fast and effective, even under heavy loads
  • MySQL 5.6 Database Administrator 1Z0-883. Oracle provides the following outline for their MySQL for Database Administrators (Ed 3.1) training course:

    Course Objectives

    • Describe the MySQL Architecture
    • Install and Upgrade MySQL
    • Use the INFORMATION_SCHEMA database to access metadata
    • Perform the MySQL start and shutdown operations
    • Configure MySQL server options at runtime
    • Use available tools including MySQL Workbench
    • Evaluate data types and character sets for performance issues
    • Understand data locking in MySQL
    • Understand the use of the InnoDB storage engine with MySQL
    • Maintain integrity of a MySQL installation
    • Use triggers for administration tasks
    • Use Enterprise Audit and Pluggable Authentication
    • Configure advanced replication topologies for high availability
    • Describe introductory performance tuning techniques
    • Perform backup and restore operations
    • Automate administrative tasks with scheduled events

    As always, I hope this helps those who read it; and, in this case I hope it helps you make an effective decision on preparation resources for the MySQL 5.6 OCP exams.

Written by maclochlainn

April 24th, 2015 at 12:39 am

Add zsh to Fedora

with one comment

One of my students requested an option to the bash shell. It was interesting to hear that he wanted me to instal the zsh in my Fedora image. There’s only one book that I’m aware of that’s been published on the Z Shell, and it is From Bash to Z Shell.

This post shows how to add the zsh to my Fedora image because I already release a new one for the term without the zsh shell. You use the yum utility as the root user to install the zsh library:

yum install -y zsh

It should produce an output stream like the following, which required accessing the alternate mirror site:

Loaded plugins: langpacks, refresh-packagekit
mysql-connectors-community                                  | 2.5 kB  00:00     
mysql-tools-community                                       | 2.5 kB  00:00     
mysql56-community                                           | 2.5 kB  00:00     
pgdg93                                                      | 3.6 kB  00:00     
updates/20/x86_64/metalink                                  |  14 kB  00:00     
updates                                                     | 4.9 kB  00:00     
(1/3): mysql-connectors-community/20/x86_64/primary_db      | 8.8 kB  00:00     
(2/3): pgdg93/20/x86_64/primary_db                          |  83 kB  00:01     
(3/3): updates/20/x86_64/primary_db                         |  13 MB  00:13     
updates/20/x86_64/pkgtags      FAILED                                           
http://mirror.utexas.edu/fedora/linux/updates/20/x86_64/repodata/1ea83dc402a2bcba53f9b0011ecfa0d579b5a316e4c7f01ec5f1166dcdca138f-pkgtags.sqlite.gz: [Errno 14] HTTP Error 404 - Not Found
Trying other mirror.
(1/2): updates/20/x86_64/updateinfo                         | 1.9 MB  00:07     
(2/2): updates/20/x86_64/pkgtags                            | 1.4 MB  00:01     
Resolving Dependencies
--> Running transaction check
---> Package zsh.x86_64 0:5.0.7-6.fc20 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
================================================================================
 Package       Arch             Version                 Repository         Size
================================================================================
Installing:
 zsh           x86_64           5.0.7-6.fc20            updates           2.5 M
 
Transaction Summary
================================================================================
Install  1 Package
 
Total download size: 2.5 M
Installed size: 5.9 M
Downloading packages:
zsh-5.0.7-6.fc20.x86_64.rpm                                 | 2.5 MB  00:03     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction (shutdown inhibited)
  Installing : zsh-5.0.7-6.fc20.x86_64                                      1/1 
  Verifying  : zsh-5.0.7-6.fc20.x86_64                                      1/1 
 
Installed:
  zsh.x86_64 0:5.0.7-6.fc20                                                     
 
Complete!

Once you’ve installed the zsh, you can configure like you would the bash shell. You make edits to individual .zshrc files and generic changes to the /etc/zshrc file. You can find the documentation to edit the zsh in the User’s Guide to the Z-Shell.

The following is a modified .zshrc file. The changes enable the up-arrow in Oracle’s sqlplus and provides you with a color prompt, like this:

# Source global definitions
if [ -f /etc/zshrc ]; then
  . /etc/zshrc
fi
 
# Uncomment the following line if you don't like systemctl's auto-paging feature:
# export SYSTEMD_PAGER=
 
# Set the JAVA_HOME path.
export JAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.75-2.5.4.2.fc20.x86_64
 
# Set the CLASSPATH path.
export CLASSPATH=/usr/share/java/mysql-connector-java.jar:.
 
# User specific aliases and functions
. /u01/app/oracle/product/11.2.0/xe/bin/oracle_env.sh
 
# Wrap sqlplus with rlwrap to edit prior lines with the
# up, down, left and right keys.
sqlplus()
{
  if [ "$RLWRAP" = "0" ]; then
    sqlplus "$@"
  else
    rlwrap sqlplus "$@"
  fi
}
 
# Set the bindkey.
bindkey -v
bindkey "^R" history-incremental-search-backward
export EDITOR="vim"
 
# history stuff
HISTFILE=~/.zsh-histfile
HISTSIZE=2000
 
# Set vi as a command line editor.
set -o vi
 
autoload -U colors && colors
PS1="[%{$fg[red]%}%n%{$reset_color%}@%{$fg[blue]%}%m %{$fg[yellow]%}%~%{$reset_color%}% ]$ "

The zsh prompt looks like the following:

[student@localhost ~]$

If you’re configured with a bash shell, you can change your shell to a zsh with the following command:

chsh -s /bin/zsh

As always, I hope this helps those looking for this type of information.

Written by maclochlainn

April 22nd, 2015 at 11:09 pm

Oracle Cleanup a Schema

with one comment

Back in January 2014, I wrote a script to cleanup an Oracle student schema. It worked well until I started using APEX 4 in my student schema. You create the following 75 objects when you create an APEX 4 schema.

OBJECT TYPE    TOTAL
------------ -------
TABLE		  17
INDEX		  28
SEQUENCE	   5
TRIGGER 	  14
LOB		   9
FUNCTION	   2

Here’s the modified script that ignores the objects created automatically by Oracle APEX when you create a student workspace:

BEGIN
  FOR i IN (SELECT    object_name
            ,         object_type
            ,         last_ddl_time
            FROM      user_objects
            WHERE     object_name NOT IN
                       ('APEX$_WS_WEBPG_SECTION_HISTORY','APEX$_WS_WEBPG_SECTIONS_T1'
                       ,'APEX$_WS_WEBPG_SECTIONS_PK','APEX$_WS_WEBPG_SECTIONS'
                       ,'APEX$_WS_WEBPG_SECHIST_IDX1','APEX$_WS_TAGS_T1'
                       ,'APEX$_WS_TAGS_PK','APEX$_WS_TAGS_IDX2','APEX$_WS_TAGS_IDX1'
                       ,'APEX$_WS_TAGS','APEX$_WS_ROWS_T1','APEX$_WS_ROWS_PK'
                       ,'APEX$_WS_ROWS_IDX','APEX$_WS_ROWS','APEX$_WS_NOTES_T1'
                       ,'APEX$_WS_NOTES_PK','APEX$_WS_NOTES_IDX2','APEX$_WS_NOTES_IDX1'
                       ,'APEX$_WS_NOTES','APEX$_WS_LINKS_T1','APEX$_WS_LINKS_PK'
                       ,'APEX$_WS_LINKS_IDX2','APEX$_WS_LINKS_IDX1','APEX$_WS_LINKS'
                       ,'APEX$_WS_HISTORY_IDX','APEX$_WS_HISTORY','APEX$_WS_FILES_T1'
                       ,'APEX$_WS_FILES_PK','APEX$_WS_FILES_IDX2','APEX$_WS_FILES_IDX1'
                       ,'APEX$_WS_FILES','APEX$_ACL_T1','APEX$_ACL_PK','APEX$_ACL_IDX1'
                       ,'APEX$_ACL','CUSTOM_AUTH','CUSTOM_HASH','DEPT','EMP'
                       ,'UPDATE_ORDER_TOTAL')
            AND NOT ((object_name LIKE 'DEMO%' OR
                      object_name LIKE 'INSERT_DEMO%' OR
                      object_name LIKE 'BI_DEMO%') AND
                      object_type IN ('TABLE','INDEX','SEQUENCE','TRIGGER'))
            AND NOT (object_name LIKE 'SYS_LOB%' AND object_type = 'LOB')
            AND NOT (object_name LIKE 'SYS_C%' AND object_type = 'INDEX')
            ORDER BY object_type DESC) LOOP
 
    /* Drop types in descending order. */
    IF i.object_type = 'TYPE' THEN
 
      /* Drop type and force operation because dependencies may exist. Oracle 12c
         also fails to remove object types with dependents in pluggable databases
         (at least in release 12.1). Type evolution works in container database
         schemas. */
      EXECUTE IMMEDIATE 'DROP '||i.object_type||' '||i.object_name||' FORCE';
 
    /* Drop table tables in descending order. */
    ELSIF i.object_type = 'TABLE' THEN
 
      /* Drop table with cascading constraints to ensure foreign key constraints
         don't prevent the action. */
      EXECUTE IMMEDIATE 'DROP '||i.object_type||' '||i.object_name||' CASCADE CONSTRAINTS PURGE';
 
      /* Oracle 12c ONLY: Purge the recyclebin to dispose of system-generated
         sequence values because dropping the table doesn't automatically 
         remove them from the active session.
         CRITICAL: Remark out the following when working in Oracle Database 11g. */
      EXECUTE IMMEDIATE 'PURGE RECYCLEBIN';
 
    ELSIF i.object_type = 'LOB' OR i.object_type = 'INDEX' THEN
 
      /* A system generated LOB column or INDEX will cause a failure in a
         generic drop of a table because it is listed in the cursor but removed
         by the drop of its table. This NULL block ensures there is no attempt
         to drop an implicit LOB data type or index because the dropping the
         table takes care of it. */
      NULL;
 
    ELSE
 
      dbms_output.put_line('DROP '||i.object_type||' '||i.object_name||';');
      /* Drop any other objects, like sequences, functions, procedures, and packages. */
      EXECUTE IMMEDIATE 'DROP '||i.object_type||' '||i.object_name;
 
    END IF;
  END LOOP;
END;
/

As always, I hope this helps others.

Written by maclochlainn

April 19th, 2015 at 7:13 pm

Ruby Thin Web Server

without comments

Somebody suggested that I try out thin, “A fast and very simple Ruby web server.” So, I thought it might be interesting to test, and a simplification over Rails to demonstrate an small Ruby MVC pattern.

Installing thin seemed straight forward as a gem installation, like

gem install thin

The initial install didn’t work out of the box because I’d neglected to install the gcc-c++ library. It raised the following errors:

Fetching: eventmachine-1.0.7.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing thin:
	ERROR: Failed to build gem native extension.
 
    /usr/bin/ruby extconf.rb
checking for main() in -lssl... no
checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... yes
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for inotify_init() in sys/inotify.h... yes
checking for writev() in sys/uio.h... yes
checking for rb_thread_fd_select()... yes
checking for rb_fdset_t in ruby/intern.h... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_enable_interrupt()... no
checking for rb_time_new()... yes
checking for sys/event.h... no
checking for epoll_create() in sys/epoll.h... yes
checking for clock_gettime()... yes
checking for CLOCK_MONOTONIC_RAW in time.h... yes
checking for CLOCK_MONOTONIC in time.h... yes
creating Makefile
 
make "DESTDIR="
g++ -I. -I/usr/include -I/usr/include/ruby/backward -I/usr/include -I. -DWITHOUT_SSL -DBUILD_FOR_RUBY -DHAVE_RB_THREAD_BLOCKING_REGION -DHAVE_TBR -DHAVE_RUBY_THREAD_H -DHAVE_RB_THREAD_CALL_WITHOUT_GVL -DHAVE_RB_THREAD_CALL_WITHOUT_GVL -DHAVE_INOTIFY_INIT -DHAVE_INOTIFY -DHAVE_WRITEV -DHAVE_WRITEV -DHAVE_RB_THREAD_FD_SELECT -DHAVE_RB_THREAD_FD_SELECT -DHAVE_TYPE_RB_FDSET_T -DHAVE_RB_FDSET_T -DHAVE_RB_WAIT_FOR_SINGLE_FD -DHAVE_RB_TIME_NEW -DOS_UNIX -DHAVE_EPOLL_CREATE -DHAVE_EPOLL -DHAVE_CLOCK_GETTIME -DHAVE_CONST_CLOCK_MONOTONIC_RAW -DHAVE_CONST_CLOCK_MONOTONIC    -fPIC -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -mtune=generic -m64 -o ed.o -c ed.cpp
make: g++: Command not found
make: *** [ed.o] Error 127
 
 
Gem files will remain installed in /usr/local/share/gems/gems/eventmachine-1.0.7 for inspection.
Results logged to /usr/local/share/gems/gems/eventmachine-1.0.7/ext/gem_make.out

Naturally, I installed the gcc-c++ library with the yum utility, like this:

yum list gcc-c++

It displayed the following log output:

Loaded plugins: langpacks, refresh-packagekit
mysql-connectors-community                                  | 2.5 kB  00:00     
mysql-tools-community                                       | 2.5 kB  00:00     
mysql56-community                                           | 2.5 kB  00:00     
pgdg93                                                      | 3.6 kB  00:00     
updates/20/x86_64/metalink                                  |  14 kB  00:00     
updates                                                     | 4.9 kB  00:00     
updates/20/x86_64/primary_db                                |  13 MB  00:04     
(1/2): updates/20/x86_64/updateinfo                         | 1.9 MB  00:02     
(2/2): updates/20/x86_64/pkgtags                            | 1.4 MB  00:00     
Resolving Dependencies
--> Running transaction check
---> Package gcc-c++.x86_64 0:4.8.3-7.fc20 will be installed
--> Processing Dependency: libstdc++-devel = 4.8.3-7.fc20 for package: gcc-c++-4.8.3-7.fc20.x86_64
--> Running transaction check
---> Package libstdc++-devel.x86_64 0:4.8.3-7.fc20 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
================================================================================
 Package                Arch          Version              Repository      Size
================================================================================
Installing:
 gcc-c++                x86_64        4.8.3-7.fc20         updates        7.2 M
Installing for dependencies:
 libstdc++-devel        x86_64        4.8.3-7.fc20         updates        1.5 M
 
Transaction Summary
================================================================================
Install  1 Package (+1 Dependent package)
 
Total download size: 8.7 M
Installed size: 25 M
Downloading packages:
(1/2): gcc-c++-4.8.3-7.fc20.x86_64.rpm                      | 7.2 MB  00:05     
(2/2): libstdc++-devel-4.8.3-7.fc20.x86_64.rpm              | 1.5 MB  00:01     
--------------------------------------------------------------------------------
Total                                              1.3 MB/s | 8.7 MB  00:06     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction (shutdown inhibited)
  Installing : libstdc++-devel-4.8.3-7.fc20.x86_64                          1/2 
  Installing : gcc-c++-4.8.3-7.fc20.x86_64                                  2/2 
  Verifying  : gcc-c++-4.8.3-7.fc20.x86_64                                  1/2 
  Verifying  : libstdc++-devel-4.8.3-7.fc20.x86_64                          2/2 
 
Installed:
  gcc-c++.x86_64 0:4.8.3-7.fc20                                                 
 
Dependency Installed:
  libstdc++-devel.x86_64 0:4.8.3-7.fc20                                         
 
Complete!

After installing the gcc-c++ libraries, I reran the gem utility to install the thin utility. It created three Ruby Gems: eventmachine-1.0.7, daemons-1.2.2.gem, and thin-1.6.3.gem, as shown:

Building native extensions.  This could take a while...
Successfully installed eventmachine-1.0.7
Fetching: daemons-1.2.2.gem (100%)
Successfully installed daemons-1.2.2
Fetching: thin-1.6.3.gem (100%)
Building native extensions.  This could take a while...
Successfully installed thin-1.6.3
Parsing documentation for daemons-1.2.2
Installing ri documentation for daemons-1.2.2
Parsing documentation for eventmachine-1.0.7
Installing ri documentation for eventmachine-1.0.7
Parsing documentation for thin-1.6.3
Installing ri documentation for thin-1.6.3
Done installing documentation for daemons, eventmachine, thin after 11 seconds
3 gems installed

Having created the Ruby Gems, I followed the thin instruction on the web site, and created the following Ruby web server:

app = proc do |env|
  [
    200,             # Status code
    {                # Response headers
      'Content-Type' => 'text/html',
      'Content-Length' => '12',
    },
    ['Hello World!'] # Response body
  ]
end
 
# You can install Rack middlewares
# to do some crazy stuff like logging,
# filtering, auth or build your own.
use Rack::CommonLogger
 
run app

Then, I tested the Ruby web server with the following command:

thin start -R thin.ru

It displayed the following test server as the result of localhost:3000 URL:

ThinRubyWebServer

As always, I hope this helps those who land on this page.

Written by maclochlainn

April 18th, 2015 at 10:00 pm

Find a string in files

with 2 comments

From time to time, folks ask questions about how to solve common problems in Linux or Unix. Today, the question is: “How do I find a list of files that contain a specific string?” There are two alternatives with the find command, and the following sample searches look for files that contain a sqlite3 string literal.

  • Search for only the file names:
find . -type f | xargs grep -li sqlite3

Or, the more verbose:

find . -type f -exec grep -li sqlite3 /dev/null {} +
  • Search for the file names and text line:
find . -type f | xargs grep -i sqlite3

Or, the more verbose:

find . -type f -exec grep -i sqlite3 /dev/null {} +

Don’t exclude the /dev/null from the verbose syntax or you’ll get the things you lack permissions to inspect or that raise other errors. I don’t post a lot of Linux or Unix tips and techniques, and you may find this site more useful to answer these types of questions:

Unix & Linux Stack Exchange web site

As always, I hope this helps those you land on the blog page.

Written by maclochlainn

April 18th, 2015 at 2:39 pm