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Using MySQL Workbench

without comments

I’ve been setting up a simplified lab environment to let my students learn use in class. This added content will show them how to do reverse engineering with MySQL Workbench.

It’s a complete Fedora image with MySQL and Oracle Database 11g for the course. The uncompressed image is 14GB and the compressed image is 5.3GB. I chose Fedora because it’s the smallest open source image that supports both environments, and Fedora is the closest to Red Hat and Oracle Unbreakable Linux. I’m inclined to make the instance available generally but haven’t figured out the best way to do that.

Here are the new instructions I’m adding and if you have any input leave it as a comment. ;-)

You connect as the student user, which puts you in the /home/student directory. Once connected to the Fedora OS, you open a Terminal session by clicking on Activities in the upper right hand corner, and then you type terminal in the search box. When you’re in the Terminal session, use the following command to verify that the apply_mysql_lab1.sql file is correct:

cat Data/cit225/mysql/lab1/apply_mysql_lab1.sql

It should display the following commands:

\. /home/student/Data/cit225/mysql/lib/cleanup.sql
\. /home/student/Data/cit225/mysql/lib/create_mysql_store_ri.sql
\. /home/student/Data/cit225/mysql/lib/seed_mysql_store_ri.sql

You can run the apply_mysql_lab1.sql to create the tables in the studentdb database, and seed them with data. Assuming you’re in the same /home/student directory, you connect to the studentdb database with the following syntax:

mysql -ustudent -pstudent studentdb

or, more securely:

mysql -ustudent studentdb -p

Having connected to the studentdb database, you can run the following command:

\. /home/student/Data/cit225/mysql/lab1/apply_mysql_lab1.sql

It creates a Video store image and seeds it with some basic data. You can use the show command to see the tables you’ve created, like:

show tables;

It displays:

+---------------------+
| Tables_in_studentdb |
+---------------------+
| address             |
| common_lookup       |
| contact             |
| contacts            |
| current_rental      |
| item                |
| member              |
| rental              |
| rental_item         |
| street_address      |
| system_user         |
| telephone           |
+---------------------+
12 rows in set (0.00 sec)

After successfully creating and seeding the studentdb database, you can run MySQL Workbench by launching it from the search field (recommended). Alternatively, you can open it from a terminal session with the following command. Unfortunately, a command-line launch links the terminal and the MySQL Workbench processes and closing the terminal will close the MySQL Workbench.

mysql-workbench

Here are the instructions for the lab with MySQL Workbench:

FedoraMySQLWorkbenchHome

  1. The first displayed page of MySQL Workbench is the home page (click on it or any of the others to see the full size image). Click the symbol to the right of the MySQL Workbench title.

MySQL_Lab3_01

  1. After clicking the the symbol, it launches the Startup New Connection dialog. Enter a name for your new connection. I recommend you enter MySQLConnection.

MySQL_Lab3_02

  1. Click the Test Connection button to see if it works.

MySQL_Lab3_03

  1. When you click the Test Connection button, MySQL Workbench prompts you for a password. After entering a password and verifying the connection, click the OK button to test the connection.

MySQL_Lab3_04

  1. Click the OK button to continue.

MySQL_Lab3_05

  1. Click the gray highlighted MySQLConnection connection icon below the MySQL Connection title to launch the MySQL Workbench application.

MySQL_Lab3_03

  1. When you click the gray highlighted MySQLConnection connection icon, MySQL Workbench prompts you for a password. After entering a password and verifying the connection, click the OK button to connect to the MySQL Workbench application.

MySQL_Lab3_06

  1. The MySQL Workbench launches in the default view.

MySQL_Lab3_07

  1. Click on the Database menu option and then the Reverse Engineering… option, as shown in the illustration.

MySQL_Lab3_08

  1. This displays the Set Parameters for Connecting to a DBMS dialog. Click the Stored Connection list of values. Choose the MySQLConnection (if you used my suggestion) or the one you created from the list of values of the Stored Connection element. Click the Next button to continue.

MySQL_Lab3_09

  1. Enter the password and click the OK button to connect to the MySQL database.

MySQL_Lab3_10

  1. This is an in-progress display, it runs waiting for the password and until the step of the wizard completes.

MySQL_Lab3_11

  1. This dialog displays when the MySQL Workbench application connects to the database, retrieves a schema (database) list from the database management system, and checks the common server configuration issues. Click the Next button to move to the next step of the wizard.

MySQL_Lab3_12

  1. This Select Schemas to Reverse Engineer dialog displays any available schemas. You check the schemas that you want. Click the Next button to move to the next step of the wizard.

MySQL_Lab3_09

  1. Enter the password and click the OK button to connect to the MySQL database to retrieve objects from the database management system.

MySQL_Lab3_14

  1. This dialog displays when the MySQL Workbench application retrieves objects from the database. Click the Next button to move to the next step of the wizard.

MySQL_Lab3_15

  1. This dialog displays when the MySQL Workbench application retrieves objects from the schemata and checks the result. Click the Next button to move to the next step of the wizard.

MySQL_Lab3_15

  1. This dialog displays the tables, views, and routines to import. Click the Execute button to move to the next step of the wizard.

MySQL_Lab3_16

  1. This dialog displays the tables, views, and routines to import. Click the Execute button to move to the next step of the wizard.

MySQL_Lab3_17

  1. This dialog displays shows the reverse engineering objects and puts them in the object image. Click the Next button to move to the next step of the wizard.

MySQL_Lab3_18

  1. This dialog displays a summary of reverse engineering objects. Click the Close button to move to the next step of the wizard.

MySQL_Lab3_19

  1. The MySQL Model dialog displays after you complete the reverse engineering process. Click the EER Diagram icon or EER Diagram tab to see visual depiction of the database objects.

MySQL_Lab3_20

  1. The EER Diagram is equivalent to the EER Diagram tab. The Navigator displays the tables as blue rectangles. You can scroll through the Canvas Panel to work with the display of tables and views.

MySQL_Lab3_21

  1. The next image shows EER Diagram with the tables moved for display purposes. Sometimes there are too many relationship lines, MySQL Workbench lets you split the lines so they don’t clutter the diagram.

MySQL_Lab3_22

  1. The next image shows you the Property tab of EER Diagram. You should see that the drawSplit checkbox is checked, which suppresses the bottom-most relationship line from displaying in the EER from display on the Canvas Panel.

You can now save the MySQL Workbench file in the Lab 3 directory.

Written by maclochlainn

September 25th, 2014 at 5:10 pm

MySQL Workbench on Fedora

with one comment

The early release of Fedora 20 disallowed installation of MySQL Workbench but the current version allows it. Almost like Tom Cruise’s Edge of Tomorrow without the drama. All you need to do is follow my earlier instructions for installing MySQL on Fedora 20. I’d check your kernel to know whether it’s supported. You can check that with this command:

<shell> uname -r

My Fedora is at the following version:

3.14.8-200.fc20.x86_64

Then, you can install MySQL Workbench with yum, like this:

<shell> sudo yum install mysql-workbench

It generates the following log file, and if you have Oracle 11g XE installed you can ignore the mime-type error:

Loaded plugins: langpacks, refresh-packagekit
Resolving Dependencies
--> Running transaction check
---> Package mysql-workbench-community.x86_64 0:6.1.7-1.fc20 will be installed
--> Processing Dependency: libzip.so.2()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Processing Dependency: libvsqlitepp.so.3()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Processing Dependency: libtinyxml.so.0()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Processing Dependency: liblua-5.1.so()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Processing Dependency: libgtkmm-2.4.so.1()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Processing Dependency: libgdkmm-2.4.so.1()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Processing Dependency: libctemplate.so.2()(64bit) for package: mysql-workbench-community-6.1.7-1.fc20.x86_64
--> Running transaction check
---> Package compat-lua-libs.x86_64 0:5.1.5-1.fc20 will be installed
---> Package ctemplate.x86_64 0:2.2-5.fc20 will be installed
---> Package gtkmm24.x86_64 0:2.24.4-2.fc20 will be installed
---> Package libzip.x86_64 0:0.11.2-1.fc20 will be installed
---> Package tinyxml.x86_64 0:2.6.2-4.fc20 will be installed
---> Package vsqlite++.x86_64 0:0.3.13-3.fc20 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
================================================================================
 Package                    Arch    Version        Repository              Size
================================================================================
Installing:
 mysql-workbench-community  x86_64  6.1.7-1.fc20   mysql-tools-community   24 M
Installing for dependencies:
 compat-lua-libs            x86_64  5.1.5-1.fc20   updates                158 k
 ctemplate                  x86_64  2.2-5.fc20     fedora                 174 k
 gtkmm24                    x86_64  2.24.4-2.fc20  fedora                 748 k
 libzip                     x86_64  0.11.2-1.fc20  updates                 59 k
 tinyxml                    x86_64  2.6.2-4.fc20   updates                 49 k
 vsqlite++                  x86_64  0.3.13-3.fc20  updates                 58 k
 
Transaction Summary
================================================================================
Install  1 Package (+6 Dependent packages)
 
Total download size: 26 M
Installed size: 119 M
Is this ok [y/d/N]: y
Downloading packages:
(1/7): compat-lua-libs-5.1.5-1.fc20.x86_64.rpm              | 158 kB  00:01     
(2/7): ctemplate-2.2-5.fc20.x86_64.rpm                      | 174 kB  00:01     
(3/7): tinyxml-2.6.2-4.fc20.x86_64.rpm                      |  49 kB  00:00     
(4/7): gtkmm24-2.24.4-2.fc20.x86_64.rpm                     | 748 kB  00:01     
(5/7): vsqlite++-0.3.13-3.fc20.x86_64.rpm                   |  58 kB  00:00     
(6/7): libzip-0.11.2-1.fc20.x86_64.rpm                      |  59 kB  00:02     
(7/7): mysql-workbench-community-6.1.7-1.fc20.x86_64.rpm    |  24 MB  00:08     
--------------------------------------------------------------------------------
Total                                              2.9 MB/s |  26 MB  00:08     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : gtkmm24-2.24.4-2.fc20.x86_64                                 1/7 
  Installing : libzip-0.11.2-1.fc20.x86_64                                  2/7 
  Installing : vsqlite++-0.3.13-3.fc20.x86_64                               3/7 
  Installing : ctemplate-2.2-5.fc20.x86_64                                  4/7 
  Installing : compat-lua-libs-5.1.5-1.fc20.x86_64                          5/7 
  Installing : tinyxml-2.6.2-4.fc20.x86_64                                  6/7 
  Installing : mysql-workbench-community-6.1.7-1.fc20.x86_64                7/7 
Error in file "/usr/share/applications/oraclexe-startdb.desktop": "Application/database" is an invalid MIME type ("Application" is an unregistered media type)
  Verifying  : tinyxml-2.6.2-4.fc20.x86_64                                  1/7 
  Verifying  : compat-lua-libs-5.1.5-1.fc20.x86_64                          2/7 
  Verifying  : ctemplate-2.2-5.fc20.x86_64                                  3/7 
  Verifying  : vsqlite++-0.3.13-3.fc20.x86_64                               4/7 
  Verifying  : mysql-workbench-community-6.1.7-1.fc20.x86_64                5/7 
  Verifying  : libzip-0.11.2-1.fc20.x86_64                                  6/7 
  Verifying  : gtkmm24-2.24.4-2.fc20.x86_64                                 7/7 
 
Installed:
  mysql-workbench-community.x86_64 0:6.1.7-1.fc20                               
 
Dependency Installed:
  compat-lua-libs.x86_64 0:5.1.5-1.fc20     ctemplate.x86_64 0:2.2-5.fc20       
  gtkmm24.x86_64 0:2.24.4-2.fc20            libzip.x86_64 0:0.11.2-1.fc20       
  tinyxml.x86_64 0:2.6.2-4.fc20             vsqlite++.x86_64 0:0.3.13-3.fc20    
 
Complete!

After successfully installing MySQL Workbench, you can launch it with the following command:

<shell> mysql-workbench

It should launch the following MySQL Workbench home page (click on it to see the full size image):

FedoraMySQLWorkbenchHome

Written by maclochlainn

September 13th, 2014 at 12:00 am

MySQL Insert from Query

with 4 comments

While working with an error that my students surfaced in the Oracle Database 12c, I blogged about the limit of using a subquery in an Oracle INSERT statement, and I discovered something when retesting it in MySQL. It was a different limitation. I was also surprised when I didn’t find any mention of it through a Google search, but then I may just not have the right keywords.

The original test case uses a subquery to create a multiple row result set for an INSERT statement. Unfortunately, I discovered that you can’t always embed a UNION or UNION ALL inside a subquery. At least, you can’t when you call the subquery inside an INSERT statement. For example, let’s create a DESTINATION table and then we’ll try to insert records with a query that fabricates a result set.

-- Drop the destination table.
DROP TABLE IF EXISTS destination;
 
-- Create the destination table.
CREATE TABLE destination
( destination_id    INT UNSIGNED
, destination_name  VARCHAR(30));

Now let’s try the subquery:

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INSERT INTO destination
( SELECT 1,'Sample1'
  UNION ALL
  SELECT 2,'Sample2' );

It raises the following error message:

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'UNION ALL
  SELECT 2,'Sample2' )' at line 3

I wasn’t sure if I missed something. It turned out that I did. While you can put a subquery inside an INSERT statement, you can’t embed it inside a set of parentheses when it contains a UNION ALL set operator. Other statements work with or without parentheses.

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INSERT INTO destination
  SELECT 1,'Sample1'
  UNION ALL
  SELECT 2,'Sample2';

If somebody has any more to add, I look forward to reading it.

Written by maclochlainn

June 15th, 2014 at 12:19 am

Posted in MySQL,sql

Tagged with

Toad Freeware Page

without comments

While I posted how to install Toad for MySQL Freeware five years ago, I’m always surprised how few people know about it there and consistently updated and improved. You can download Toad for MySQL Freeware or Toad Freeware for Oracle, SQL Server, Sybase, or IBM DB2 at this web site.

MySQLToadHome

You can also download Toad Data Modeler Freeware Edition. Just two notes, while Toad for Oracle Freeware is an MSI file, Toad for MySQL Freeware is a zip file and limited to only a Windows install.

Written by maclochlainn

April 30th, 2014 at 1:46 am

A/UX, NeXTSTEP, & OS X

with 5 comments

One thing that gets tedious in the IT community and Oracle community is the penchant for Windows only solutions. While Microsoft does an excellent job in certain domains, I remain a loyal Apple customer. By the way, you can install Oracle Client software on Mac OS X and run SQL Developer against any Oracle Database server. You can even run MySQL Workbench and MySQL server natively on the Mac OS X platform, which creates a robust development platform and gives you more testing options with the MySQL monitor (the client software).

Notwithstanding, some Windows users appear to malign Apple and the Mac OS X on compatibility, but they don’t understand that it’s a derivative of the Research Unix, through BSD (Berkeley Software Distribution). This Unix lineage chart illustrates it well:

Screen Shot 2014-04-18 at 3.49.39 PM

I’m probably loyal to Apple because in the early 1990’s I worked on Mac OS 6, Mac OS 7, A/UX, NeXTSTEP, and AIX/6000 (Version 3) while working at APL (American President Lines) in Oakland, California. Back then, my desktop was a pricey Macintosh Quadra 950 and today I work on a pricey Mac Pro desktop. The Mac Pro lets me use VMware virtualize development environments for Oracle Linux, Red Hat Enterprise Linux, Fedora, and as you might guess Windows 7/8. My question to those dyed in the wool Microsoft users is simple, why would you choose a single user OS like Windows over a multi-user OS like Mac OS X?

Written by maclochlainn

April 18th, 2014 at 4:28 pm

Deprecated mysqli Functions

without comments

PHPDeprecation5_4

Having noticed the release of PHP 5.5.10 last week while I was speaking at UTOUG, I checked the deprecated mysqli functions web page. There weren’t any deprecated by 5.5. Unfortuantely, there were six mysqli functions deprecated in 5.3 and removed in 5.4. Unfortunately, many of my posted code examples use 5.2 or 5.3 where they would have worked. The deprecated mysqli functions are:

  • mysqli_bind_param
  • mysqli_bind_result
  • mysqli_client_encoding
  • mysqli_fetch
  • mysqli_param_count
  • mysqli_send_long_data

Unfortunately, that puts a lot of updates on my queue of things to do. I imagine it likewise imposes limits on those running commercially on PHP 5.3 or older that plan an upgrade.

It does remind me that I need to pay close attention to the deprecation of mysqli functions with each release. These are actually the largest change since PHP 5.0.

Written by maclochlainn

March 18th, 2014 at 12:28 pm

Posted in MySQL,mysqli,PHP

Tagged with , ,

Capture MySQL Foreign Keys

with one comment

Shantanu asked a follow-up question on my Cleanup a MySQL Schema post from last month. He wanted to know if there was a way to capture foreign keys before removing them. The answer is yes, but how you do it depends on whether the primary key is based on a surrogate key using an auto incrementing sequence of a natural key using descriptive columns.

You can capture foreign keys with a simple query when they’re determined by a single column value. However, this script creates ALTER statements that will fail when a table holds a multiple column foreign key value. The SELECT statement would look like this when capturing all foreign key values in a MySQL Server:

SELECT   CONCAT('ALTER TABLE',' ',tc.table_schema,'.',tc.table_name,' '
               ,'ADD CONSTRAINT',' fk_',tc.constraint_name,' '
               ,'FOREIGN KEY (',kcu.column_name,')',' '
               ,'REFERENCES',' ',kcu.referenced_table_schema,'.',kcu.referenced_table_name,' ' 
               ,'(',kcu.referenced_column_name,');') AS script
FROM     information_schema.table_constraints tc JOIN information_schema.key_column_usage kcu
ON       tc.constraint_name = kcu.constraint_name
AND      tc.constraint_schema = kcu.constraint_schema
WHERE    tc.constraint_type = 'foreign key'
ORDER BY tc.TABLE_NAME
,        kcu.column_name;

You would add a line in the WHERE clause to restrict it to a schema and a second line to restrict it to a table within a schema, like this:

AND      tc.table_schema = 'your_mysql_database'
AND      tc.table_name = 'your_table_name'

Unfortunately, when the primary and foreign keys involve two or more columns you require a procedure and function. The function because you need to read two cursors, and the NOT FOUND can’t be nested in the current deployment of MySQL’s SQL/PSM stored programs. In this example the storedForeignKeys procedure finds the table’s foreign key constraints, and the columnList function adds the column detail. The command_list table stores the commands to restore foreign key constraints.

The command_list table that stores the values is:

CREATE TABLE command_list
( command_list_id  INT UNSIGNED PRIMARY KEY AUTO_INCREMENT
, sql_command      VARCHAR(6)    NOT NULL
, sql_object       VARCHAR(10)   NOT NULL
, sql_constraint   VARCHAR(11)
, sql_statement    VARCHAR(768)  NOT NULL);

This is the storedForeignKeys procedure:

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CREATE PROCEDURE storeForeignKeys
( pv_schema_name  VARCHAR(64)
, pv_table_name   VARCHAR(64))
BEGIN
 
  /* Declare local variables. */
  DECLARE lv_schema_name              VARCHAR(64);
  DECLARE lv_table_name               VARCHAR(64);
  DECLARE lv_constraint_name          VARCHAR(64);
  DECLARE sql_stmt                    VARCHAR(1024);
 
  /* Declare control variable for handler. */
  DECLARE fetched    INT DEFAULT 0;
 
  /* Declare local cursor for foreign key table, it uses null replacement
     because the procedure supports null parameters. When you use null 
     parameters, you get all foreign key values. */
  DECLARE foreign_key_table CURSOR FOR
    SELECT   tc.table_schema
    ,        tc.table_name
    ,        tc.constraint_name
    FROM     information_schema.table_constraints tc
    WHERE    tc.table_schema = IFNULL(lv_schema_name, tc.table_schema)
    AND      tc.table_name = IFNULL(lv_table_name, tc.table_name)
    AND      tc.constraint_type = 'FOREIGN KEY'
    ORDER BY tc.table_name;
 
  /* Declare a not found record handler to close a cursor loop. */
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET fetched = 1;
 
  /* Assign parameter values to local variables. */
  SET lv_schema_name := pv_schema_name;
  SET lv_table_name := pv_table_name;
 
  /* Open a local cursor. */  
  OPEN foreign_key_table;
  cursor_foreign_key_table: LOOP
 
    /* Fetch a row into the local variables. */
    FETCH foreign_key_table
    INTO  lv_schema_name
    ,     lv_table_name
    ,     lv_constraint_name;
 
    /* Catch handler for no more rows found from the fetch operation. */
    IF fetched = 1 THEN LEAVE cursor_foreign_key_table; END IF;
 
    /* The nested calls to the columnList function returns the list of columns
       in the foreign key. Surrogate primary to foreign keys can be resolved 
       with a simply query but natural primary to foreign key relationships
       require the list of columns involved in the primary and foreign key.
       The columnList function returns the list of foreign key columns in 
       the dependent table and the list of referenced columns (or the primary
       key columns) in the independent table. */
    SET sql_stmt := CONCAT('ALTER TABLE ',' ',lv_schema_name,'.',lv_table_name,' '
                          ,'ADD CONSTRAINT ',lv_constraint_name,' '
                          ,'FOREIGN KEY (',columnList(lv_schema_name,lv_table_name,lv_constraint_name));
 
    /* Record the SQL statements. */
    INSERT INTO command_list
    ( sql_command
    , sql_object
    , sql_constraint
    , sql_statement )
    VALUES
    ('ALTER'
    ,'TABLE'
    ,'FOREIGN KEY'
    , sql_stmt );
 
  END LOOP cursor_foreign_key_table;
  CLOSE foreign_key_table;  
 
END;
$$

This is the columnList function:

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CREATE FUNCTION columnList
( pv_schema_name      VARCHAR(64)
, pv_table_name       VARCHAR(64)
, pv_constraint_name  VARCHAR(64)) RETURNS VARCHAR(512)
BEGIN
 
  /* Declare local variables. */
  DECLARE lv_schema_name              VARCHAR(64);
  DECLARE lv_table_name               VARCHAR(64);
  DECLARE lv_constraint_name          VARCHAR(64);
  DECLARE lv_column_count             INT UNSIGNED;
  DECLARE lv_column_name              VARCHAR(64);
  DECLARE lv_column_list              VARCHAR(512);
  DECLARE lv_column_ref_list          VARCHAR(64);
  DECLARE lv_referenced_table_schema  VARCHAR(64);
  DECLARE lv_referenced_table_name    VARCHAR(64);
  DECLARE lv_referenced_column_name   VARCHAR(64);
  DECLARE lv_return_string            VARCHAR(768);
 
  /* Declare control variable for handler. */
  DECLARE fetched    INT DEFAULT 0;
 
  /* Declare local cursor for foreign key column. */
  DECLARE foreign_key_column CURSOR FOR
    SELECT   kcu.column_name
    ,        kcu.referenced_table_schema
    ,        kcu.referenced_table_name
    ,        kcu.referenced_column_name
    FROM     information_schema.key_column_usage kcu
    WHERE    kcu.referenced_table_schema = lv_schema_name
    AND      kcu.table_name = lv_table_name
    AND      kcu.constraint_name = lv_constraint_name
    ORDER BY kcu.column_name;
 
  /* Declare a not found record handler to close a cursor loop. */
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET fetched = 1;
 
  /* Assign parameter values to local variables. */
  SET lv_schema_name := pv_schema_name;
  SET lv_table_name := pv_table_name;
  SET lv_constraint_name := pv_constraint_name;
 
  /* Set the first column value. */
  SET lv_column_count := 1;
 
  /* Open the nested cursor. */
  OPEN  foreign_key_column;
  cursor_foreign_key_column: LOOP
 
    /* Fetch a row into the local variables. */    
    FETCH foreign_key_column
    INTO  lv_column_name
    ,     lv_referenced_table_schema
    ,     lv_referenced_table_name
    ,     lv_referenced_column_name;
 
    /* Catch handler for no more rows found from the fetch operation. */
    IF fetched = 1 THEN LEAVE cursor_foreign_key_column; END IF;
 
    /* Initialize the column list or add to it. */
    IF lv_column_count = 1 THEN
      SET lv_column_list := lv_column_name;
      SET lv_column_ref_list := lv_referenced_column_name;
 
      /* Increment the counter value. */
      SET lv_column_count := lv_column_count + 1;
    ELSE
      SET lv_column_list := CONCAT(lv_column_list,',',lv_column_name);
      SET lv_column_ref_list := CONCAT(lv_column_ref_list,',',lv_referenced_column_name);
    END IF;
 
  END LOOP cursor_foreign_key_column;
  CLOSE foreign_key_column;
 
  /* Set the return string to a list of columns. */
  SET lv_return_string :=
        CONCAT(lv_column_list,')',' '
              ,'REFERENCES',' ',lv_referenced_table_schema,'.',lv_referenced_table_name,' ' 
              ,'(',lv_column_ref_list,');');
 
  RETURN lv_return_string;
END;
$$

You can call the procedure with a schema and table name, and you’ll get the foreign keys from just that table. You can create the following parent and child tables to test how multiple column foreign keys work in the script (provided because most folks use surrogate keys):

CREATE TABLE parent
( first_name  VARCHAR(20)  NOT NULL DEFAULT ''
, last_name   VARCHAR(20)  NOT NULL DEFAULT ''
, PRIMARY KEY (first_name, last_name)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
CREATE TABLE child
( child_name  VARCHAR(20)  NOT NULL
, first_name  VARCHAR(20)  DEFAULT NULL
, last_name   VARCHAR(20)  DEFAULT NULL
, PRIMARY KEY (child_name)
, KEY fk_parent(first_name, last_name)
, CONSTRAINT fk_parent FOREIGN KEY (first_name, last_name)
  REFERENCES parent (first_name, last_name)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

You call the storeForeignKeys procedure for the child table with this syntax:

CALL storeForeignKeys('studentdb', 'child');

You call the storeForeignKeys procedure for all tables in a schema with this syntax:

CALL storeForeignKeys('studentdb', null);

While unlikely you’ll need this, the following calls the storeForeignKeys procedure for all tables in all schemas:

CALL storeForeignKeys(null, null);

You can export the command sequence with the following command to a script file:

SELECT sql_statement
INTO OUTFILE 'c:/Data/MySQL/apply_foreign_keys.sql'
FIELDS TERMINATED BY ','
OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY '\r\n'
FROM command_list;

While preservation of tables and foreign keys is best managed by using a tool, like MySQL Workbench, it’s always handy to have scripts to do specific tasks. I hope this helps those looking for how to preserve foreign keys. You also can find a comprehensive treatment on how to write SQL/PSM code in Chapter 14 of my Oracle Database 11g and MySQL 5.6 Developer Handbook.

Written by maclochlainn

March 17th, 2014 at 11:27 pm

Add User Defined Types

with one comment

Somebody asked me if there was a cheaper alternative to using the Embarcadero Data Architect (a data modeling tool). I said sure, you can use the MySQL Workbench. My friend laughed and said, it’s to model Oracle databases and they use different data types. I broke the news to him that he can create his own user defined types and use MySQL Workbench to model problems for the Oracle Database 11g.

For example, you can launch the MySQL Workbench, and click on the Model menu option, and in the menu window click on the User Defined Types choice, as shown in the following:

UserDefinedType

Choosing the User Defined Type option, launches the following form. You can enter customized user defined types in the User Defined Types module:

MySQLWB_UserDefinedTypes01

You enter user defined types by entering a name value and choosing valid MySQL type value before clicking the Add button. When you’ve added your last user defined type, click the OK button instead of the Add button. The next screen shot shows how you can create Oracle Database 11g native data types, specifically the NUMBER and VARCHAR2 data types.

MySQLWB_UserDefinedTypes02

Hopefully, this has shown that you can create User Defined Types let you use MySQL Workbench to create Oracle ERD models. Here’s an example of a table with Oracle’s NUMBER and VARCHAR2 data types:

CustomGLTable

Yes, MySQL Workbench is a marvelous tool with wide potential for use to solve problems with MySQL and other databases.

Written by maclochlainn

February 28th, 2014 at 2:03 am

Relationship Notations

without comments

One of my students asked how to convert MySQL Workbench’s default Crow’s Foot (IE) diagram to one of the other supported formats – Classic, Connect to Columns, UML, and IDEF1X. Crow’s Foot is also known as the Information Engineering Model method (covered in Chapter 3 of my MySQL Workbench: Data Modeling & Development.

It quite simple, you open the Model Overview window, click on the Model menu choice. In the dialog, click on the Relationship Notation menu option. Click on one of the choices in the nested menu, like Column to Columns.

ModifyRelationNotations

Hope this helps those working with MySQL Workbench.

Written by maclochlainn

February 27th, 2014 at 1:22 am

MySQL Image Architecture

with 14 comments

The LinkedIn MySQL DB Development group posed a questions on how to handle images. Naturally, the argument always goes: Should images be deployed in the database or the file system? I believe they should be stored in the database because the cost and time associated is too high with regard to managing files, a file naming schema, and backing up the file system discretely from the database.

Since there’s a significant difference between the backup of transactional data and image data, they should be placed in different databases. The imagedb database is where you would place the images and large text descriptions, as shown in the MySQL Workbench ERD:

imagedb ERD

The imagedb ERD splits the foreign key references back to the system_user table, which contains the individual user credentials. The system_user table serves as the Access Control List (ACL) for the application.

Until I get a chance to write the code for this model, you can refer to the generic PHP/MySQL solution from several years back (its code source was last tested with PHP 5.3). As always, I hope this helps.

Written by maclochlainn

February 23rd, 2014 at 2:02 am