Archive for the ‘Oracle’ Category
Oracle 11g XE APEX
The question for most new Oracle users is what’s Apex? They have a different question When they discover how to connect to the Oracle Database 11g XE default instance with this URL:
http://localhost:8080/apex |
You’ll see the following web site, and wonder what do I enter for the Workspace, the Username, and the Password values?
The answers are:
- Default Workspace: INTERNAL
- Default User: ADMIN
- Default Password:
SYSorSYSTEMPassword from Install
Enter those values within the initial password time interval and you’ll arrive at the next screen where you can manage the Oracle Database 11g XE instance. If you wait too long, you’ll be redirected to enter the original SYS or SYSTEM password from install and a new password twice. The rules for a new password are:
- Password must contain at least 6 characters.
- New password must differ from old password by at least 2 characters.
- Password must contain at least one numeric character (0123456789).
- Password must contain at least one punctuation character (!”#$%&()“*+,-/:;<=>?_).
- Password must contain at least one upper-case alphabetic character.
- Password must not contain username.
Whether you go directly to the next screen or have to enter your a new password, you should see the following screen:
You can find the default configuration for the installation with the following anonymous PL/SQL block:
DECLARE /* Declare variables. */ lv_endpoint NUMBER := 1; lv_host VARCHAR2(80); lv_port NUMBER; lv_protocol NUMBER; BEGIN /* Check for current XDB settings. */ dbms_xdb.getlistenerendpoint( lv_endpoint , lv_host , lv_port , lv_protocol ); /* Print the values. */ dbms_output.put_line('Endpoint: ['||lv_endpoint||']'||CHR(10)|| 'Host: ['||lv_host||']'||CHR(10)|| 'Port: ['||lv_port||']'||CHR(10)|| 'Protocol: ['||lv_protocol||']'); END; / |
It should print the following:
Endpoint: [1] Host: [localhost] Port: [8080] Protocol: [1] |
This is a standalone configuration and you can’t connect to the XDB server from another machine. You can only connect from the local machine.
I hope this helps those trying to use the default Apex 4 installation provided as part of the Oracle Database 11g XE instance. You can read an older post of mine that shows you how to set up a basic Workspace, but after reflection I’ll write more about creating and managing workspaces.
Functions disallow NDS
My students asked if you could embed an OFFSET x ROWS FETCH NEXT y ROWS ONLY clause in a SQL Server T-SQL user-defined function. The answer is no, it isn’t Oracle (yes, you can do that in Oracle Database 12c with an NDS statement). There’s an example in Chapter 2 of my Oracle Database 12c PL/SQL Programming book if you’re interested. I also demonstrate a different approach to SQL Server T-SQL table functions in this older post. However, an attempt to add the clause to a SQL Server T-SQL function, like this:
CREATE FUNCTION studentdb.getBatch (@rows AS INT ,@offset AS INT) RETURNS @output TABLE ( marvel_id INT , avenger_name VARCHAR(30) , first_name VARCHAR(20) , last_name VARCHAR(20)) AS BEGIN /* Insert the results into the table variable. */ INSERT @output SELECT marvel_id , avenger_name , first_name , last_name FROM studentdb.marvel OFFSET (@offset - 1) ROWS FETCH NEXT @rows ROWS ONLY; /* Return the table variable from the function. */ RETURN; END; |
Throws the following errors trying to compile the function:
Msg 102, Level 15, State 1, Procedure getBatch, Line 16 Incorrect syntax near '@offset'. Msg 153, Level 15, State 2, Procedure getBatch, Line 16 Invalid usage of the option NEXT in the FETCH statement. |
If you have a strong background in Oracle and can sort through the dynamic SQL syntax for T-SQL, you might try re-writing the function to use the EXEC SP_EXECUTESQL @var; command. That rewrite that attempts to use NDS (Native Dynamic SQL) would look like this:
CREATE FUNCTION studentdb.getBatch (@rows AS INT ,@offset AS INT) RETURNS @output TABLE ( marvel_id INT , avenger_name VARCHAR(30) , first_name VARCHAR(20) , last_name VARCHAR(20)) AS BEGIN DECLARE /* Declare a variable for a dynamic SQL statement. */ @stmt VARCHAR(400); /* Assign the SQL statement to a variable. */ SET @stmt = N'SELECT marvel_id ' + N', avenger_name ' + N', first_name ' + N', last_name ' + N'FROM studentdb.marvel ' + N'OFFSET ' + (@offset - 1) + N' ' + N'ROWS FETCH NEXT ' + @rows + N' ROWS ONLY;'; BEGIN /* Insert the results into the table variable. */ INSERT @output EXEC sp_executesql @stmt; END; /* Return the table variable from the function. */ RETURN; END; |
Throws the following exception because you can’t use dynamic dispatch inside a T-SQL function:
Msg 443, Level 16, State 14, Procedure getBatch, Line 23 Invalid use of a side-effecting operator 'INSERT EXEC' within a function. |
On the other hand you can rewrite the statement with a BETWEEN operator and it works somewhat like an OFFSET and FETCH operation. That refactored function would be written as follows:
CREATE FUNCTION studentdb.getBatch (@rowa AS INT ,@rowb AS INT) RETURNS @output TABLE ( marvel_id INT , avenger_name VARCHAR(30) , first_name VARCHAR(20) , last_name VARCHAR(20)) AS BEGIN /* Insert the results into the table variable. */ INSERT @output SELECT marvel_id , avenger_name , first_name , last_name FROM studentdb.marvel WHERE marvel_id BETWEEN @rowa AND @rowb; /* Return the table variable from the function. */ RETURN; END; |
It doesn’t raise an exception. You can call the table function like this:
SELECT * FROM getBatch(2,3); |
It returns the two rows for Iron Man and Black Widow. As always, I hope this helps.
If you want to create the test case, here’s the script you need:
SELECT 'Conditionally drop studentdb.marvel table.' AS "Statement"; IF OBJECT_ID('studentdb.marvel','U') IS NOT NULL DROP TABLE studentdb.marvel; SELECT 'Create studentdb.marvel table.' AS "Statement"; CREATE TABLE studentdb.marvel ( marvel_id INT NOT NULL IDENTITY(1,1) CONSTRAINT marvel_pk PRIMARY KEY , avenger_name VARCHAR(30) NOT NULL , first_name VARCHAR(20) NOT NULL , last_name VARCHAR(20) NOT NULL); /* Insert the rows. */ INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Hulk','Bruce','Banner'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Iron Man','Tony','Stark'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Black Widow','Natasha','Romanoff'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Thor','Thor','Odinsson'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Captain America','Steve','Rogers'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Hawkeye','Clint','Barton'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Winter Soldier','Bucky','Barnes'); INSERT INTO studentdb.marvel (avenger_name, first_name, last_name) VALUES ('Iron Patriot','James','Rhodey'); /* Query the contents of the MARVEL table. */ SELECT * FROM studentdb.marvel; |
Filtering String Dates
A question came up about how to verify dates from a string without throwing a casting error because of a non-conforming date. You can throw a number of exceptions, and I wrote a function to filter bad string formats like the DD-MON-RR or DD-MON-YYYY.
The first one is for a day between 1 and the last day of month, which is:
ORA-01847: day of month must be between 1 and last day of month |
An incorrect string for a month, raises the following error:
ORA-01843: not a valid month |
A date format mask longer than a DD-MON-RR or DD-MON-YYYY raises the following exception:
ORA-01830: date format picture ends before converting entire input string |
The verify_date function checks for non-conforming DD-MON-RR and DD-MON-YYYY date masks, and substitutes a SYSDATE value for a bad date entry:
CREATE OR REPLACE FUNCTION verify_date ( pv_date_in VARCHAR2) RETURN DATE IS /* Local return variable. */ lv_date DATE; BEGIN /* Check for a DD-MON-RR or DD-MON-YYYY string. */ IF REGEXP_LIKE(pv_date_in,'^[0-9]{2,2}-[ADFJMNOS][ACEOPU][BCGLNPRTVY]-([0-9]{2,2}|[0-9]{4,4})$') THEN /* Case statement checks for 28 or 29, 30, or 31 day month. */ CASE /* Valid 31 day month date value. */ WHEN SUBSTR(pv_date_in,4,3) IN ('JAN','MAR','MAY','JUL','AUG','OCT','DEC') AND TO_NUMBER(SUBSTR(pv_date_in,1,2)) BETWEEN 1 AND 31 THEN lv_date := pv_date_in; /* Valid 30 day month date value. */ WHEN SUBSTR(pv_date_in,4,3) IN ('APR','JUN','SEP','NOV') AND TO_NUMBER(SUBSTR(pv_date_in,1,2)) BETWEEN 1 AND 30 THEN lv_date := pv_date_in; /* Valid 28 or 29 day month date value. */ WHEN SUBSTR(pv_date_in,4,3) = 'FEB' THEN /* Verify 2-digit or 4-digit year. */ IF (LENGTH(pv_date_in) = 9 AND MOD(TO_NUMBER(SUBSTR(pv_date_in,8,2)) + 2000,4) = 0 OR LENGTH(pv_date_in) = 11 AND MOD(TO_NUMBER(SUBSTR(pv_date_in,8,4)),4) = 0) AND TO_NUMBER(SUBSTR(pv_date_in,1,2)) BETWEEN 1 AND 29 THEN lv_date := pv_date_in; ELSE /* Not a leap year. */ IF TO_NUMBER(SUBSTR(pv_date_in,1,2)) BETWEEN 1 AND 28 THEN lv_date := pv_date_in; ELSE lv_date := SYSDATE; END IF; END IF; ELSE /* Assign a default date. */ lv_date := SYSDATE; END CASE; ELSE /* Assign a default date. */ lv_date := SYSDATE; END IF; /* Return date. */ RETURN lv_date; END; / |
You can check valid dates with a DD-MON-RR format:
SELECT verify_date('28-FEB-10') AS "Non-Leap Year" , verify_date('29-FEB-12') AS "Leap Year" , verify_date('31-MAR-14') AS "31-Day Year" , verify_date('30-APR-14') AS "30-Day Year" FROM dual; |
You can check valid dates with a DD-MON-YYYY format:
SELECT verify_date('28-FEB-2010') AS "Non-Leap Year" , verify_date('29-FEB-2012') AS "Leap Year" , verify_date('31-MAR-2014') AS "31-Day Year" , verify_date('30-APR-2014') AS "30-Day Year" FROM dual; |
They both return:
Non-Leap Leap YEAR 31-DAY YEAR 30-DAY YEAR ----------- --------- ----------- ----------- 28-FEB-10 29-FEB-12 31-MAR-14 30-APR-14 |
You can check badly formatted dates with the following query:
SELECT verify_date('28-FEB-2010') AS "Non-Leap Year" , verify_date('29-FEB-2012') AS "Leap Year" , verify_date('31-MAR-2014') AS "31-Day Year" , verify_date('30-APR-2014') AS "30-Day Year" FROM dual; |
You can screen for an alphanumeric string with the following expression:
SELECT 'Valid alphanumeric string literal' AS "Statement" FROM dual WHERE REGEXP_LIKE('Some Mythical String $200','([:alnum:]|[:punct:]|[:space:])*'); |
You can screen for a numeric literal as a string with the following expression:
SELECT 'Valid numeric literal' AS "Statement" FROM dual WHERE REGEXP_LIKE('123.00','([:digit:]|[:punct:])'); |
As always, I hope this helps those who need this type of solution.
Convert to SQL Server?
I’m always amazed at the questions that pop up for me. For example, how do you convert an Oracle script that creates my Video Store model to a Microsoft SQL Server script. It’s not very hard but there’s one big caveat, and that’s the fact that system_user is a reserved word. That means you can’t create the Access Control List (ACL) table with a system_user name. The alternative, would be to convert the system_user table name to database_user. That’s what I’ve done in this example.
It’s also important to note that this example uses Microsoft SQL Server’s sqlcmd in batch mode. Naturally, it presumes that you’ve created a student user with a trivial password of student, and a studentdb schema. Also, that you’ve granted privileges so everything works (if you need help on that check my earlier post on how to setup a studentdb schema).
The following is an example of conditionally dropping and then creating a system_user table in an Oracle schema. It uses a CASCADE CONSTRAINTS clause to eliminate dependencies with foreign key values.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | -- Conditionally drop the table and sequence. BEGIN FOR i IN (SELECT NULL FROM user_tables WHERE table_name = 'SYSTEM_USER') LOOP EXECUTE IMMEDIATE 'DROP TABLE system_user CASCADE CONSTRAINTS'; END LOOP; FOR i IN (SELECT NULL FROM user_sequences WHERE sequence_name = 'SYSTEM_USER_S1') LOOP EXECUTE IMMEDIATE 'DROP SEQUENCE system_user_s1'; END LOOP; END; / |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | -- Create SYSTEM_USER table. CREATE TABLE system_user ( system_user_id NUMBER CONSTRAINT system_user_pk PRIMARY KEY , system_user_name VARCHAR2(20) CONSTRAINT system_user_nn1 NOT NULL , system_user_group_id NUMBER CONSTRAINT system_user_nn2 NOT NULL , system_user_type NUMBER CONSTRAINT system_user_nn3 NOT NULL , first_name VARCHAR2(20) , middle_name VARCHAR2(20) , last_name VARCHAR2(20) , created_by NUMBER CONSTRAINT system_user_nn4 NOT NULL , creation_date DATE CONSTRAINT system_user_nn5 NOT NULL , last_updated_by NUMBER CONSTRAINT system_user_nn6 NOT NULL , last_update_date DATE CONSTRAINT system_user_nn7 NOT NULL , CONSTRAINT system_user_fk1 FOREIGN KEY (created_by) REFERENCES system_user (system_user_id) , CONSTRAINT system_user_fk2 FOREIGN KEY (last_updated_by) REFERENCES system_user (system_user_id)); -- Create SYSTEM_USER_S1 sequence with a start value of 1001. CREATE SEQUENCE system_user_s1 START WITH 1001; |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | -- Conditionally drop the table and sequence. BEGIN FOR i IN (SELECT NULL FROM user_tables WHERE table_name = 'COMMON_LOOKUP') LOOP EXECUTE IMMEDIATE 'DROP TABLE common_lookup CASCADE CONSTRAINTS'; END LOOP; FOR i IN (SELECT NULL FROM user_sequences WHERE sequence_name = 'COMMON_LOOKUP_S1') LOOP EXECUTE IMMEDIATE 'DROP SEQUENCE common_lookup_s1'; END LOOP; END; / |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | -- Create COMMON_LOOKUP table. CREATE TABLE common_lookup ( common_lookup_id NUMBER , common_lookup_context VARCHAR2(30) CONSTRAINT nn_clookup_1 NOT NULL , common_lookup_type VARCHAR2(30) CONSTRAINT nn_clookup_2 NOT NULL , common_lookup_meaning VARCHAR2(30) CONSTRAINT nn_clookup_3 NOT NULL , created_by NUMBER CONSTRAINT nn_clookup_4 NOT NULL , creation_date DATE CONSTRAINT nn_clookup_5 NOT NULL , last_updated_by NUMBER CONSTRAINT nn_clookup_6 NOT NULL , last_update_date DATE CONSTRAINT nn_clookup_7 NOT NULL , CONSTRAINT pk_c_lookup_1 PRIMARY KEY(common_lookup_id) , CONSTRAINT fk_c_lookup_1 FOREIGN KEY(created_by) REFERENCES system_user(system_user_id) , CONSTRAINT fk_c_lookup_2 FOREIGN KEY(last_updated_by) REFERENCES system_user(system_user_id)); -- Create a non-unique index on a single column. CREATE INDEX common_lookup_n1 ON common_lookup(common_lookup_context); -- Create a unique index based on two columns. CREATE UNIQUE INDEX common_lookup_u2 ON common_lookup(common_lookup_context,common_lookup_type); -- Create COMMON_LOOKUP_S1 sequence with a start value of 1001. CREATE SEQUENCE common_lookup_s1 START WITH 1001; |
You can do the same thing for a database_user table in Microsoft SQL Server with the following syntax. Unfortunately, there isn’t a CASCADE CONSTRAINTS clause that we can append in Microsoft SQL Server. The script uses a dynamic SQL statement with a Common Table Expression (CTE) to generate a list of ALTER statements that drop foreign key constraints in the schema.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | /* Drop all foreign keys. */ USE studentdb; /* Create a session variable to hold a command list. */ SELECT 'Create a session variable.' AS "Statement"; DECLARE @sql NVARCHAR(MAX) = N''; /* Generate the command list to drop foreign key constraints. */ SELECT 'Generate dynamic SQL statements.' AS "Statement"; ;WITH x AS (SELECT N'ALTER TABLE ' + OBJECT_SCHEMA_NAME(parent_object_id) + N'.' + OBJECT_NAME(parent_object_id) + N' ' + N'DROP CONSTRAINT ' + name + N';' AS sqlstmt FROM sys.foreign_keys) SELECT @sql += sqlstmt FROM x; /* Call the dynamically generated statements. */ SELECT 'Execute dynamic SQL statements.' AS "Statement"; EXEC sp_executesql @sql; /* Conditionally drop tables. */ SELECT 'Conditionally drop studentdb.common_lookup table.' AS "Statement"; IF OBJECT_ID('studentdb.database_user','U') IS NOT NULL DROP TABLE studentdb.database_user; /* Create a table with self-referencing foreign key constraints. */ SELECT 'Create studentdb.common_lookup table.' AS "Statement"; CREATE TABLE studentdb.database_user ( database_user_id INT NOT NULL IDENTITY(1,1) CONSTRAINT database_user_pk PRIMARY KEY , database_user_name VARCHAR(20) NOT NULL , database_user_group_id INT NOT NULL , database_user_type INT NOT NULL , first_name VARCHAR(20) , middle_name VARCHAR(20) , last_name VARCHAR(20) , created_by INT NOT NULL , creation_date DATE NOT NULL , last_updated_by INT NOT NULL , last_update_date DATE NOT NULL , CONSTRAINT database_user_fk1 FOREIGN KEY (created_by) REFERENCES studentdb.database_user (database_user_id) , CONSTRAINT database_user_fk2 FOREIGN KEY (created_by) REFERENCES studentdb.database_user (database_user_id)); /* Conditionally drop common_lookup table. */ SELECT 'Conditionally drop studentdb.common_lookup table.' AS "Statement"; IF OBJECT_ID('studentdb.common_lookup','U') IS NOT NULL DROP TABLE studentdb.common_lookup; /* Create a table with external referencing foreign key constraints. */ SELECT 'Create studentdb.common_lookup table.' AS "Statement"; CREATE TABLE studentdb.common_lookup ( common_lookup_id INT NOT NULL IDENTITY(1,1) CONSTRAINT common_lookup_pk PRIMARY KEY , common_lookup_context VARCHAR(30) CONSTRAINT nn_clookup_1 NOT NULL , common_lookup_type VARCHAR(30) CONSTRAINT nn_clookup_2 NOT NULL , common_lookup_meaning VARCHAR(30) CONSTRAINT nn_clookup_3 NOT NULL , created_by INT CONSTRAINT nn_clookup_4 NOT NULL , creation_date DATE CONSTRAINT nn_clookup_5 NOT NULL , last_updated_by INT CONSTRAINT nn_clookup_6 NOT NULL , last_update_date DATE CONSTRAINT nn_clookup_7 NOT NULL , CONSTRAINT common_lookup_fk1 FOREIGN KEY(created_by) REFERENCES studentdb.database_user (database_user_id) , CONSTRAINT common_lookup_fk2 FOREIGN KEY(last_updated_by) REFERENCES studentdb.database_user (database_user_id)); |
You can run it from a file by calling the sqlcmd utility. You’ll need to know several things to run it. First, you need to know your database instance. You can capture that from a query against the data dictionary or catalog. Just run the following from inside the Microsoft SQL Server Management Studio (SSMS):
SELECT @@SERVERNAME; |
In my case, it shows the following, which is the machine’s hostname a backslash and SQLEXPRESS:
MCLAUGHLINSQL\SQLEXPRESS |
The script uses sqltest.sql as a file name, and you can call it from the Windows shell environment like this:
sqlcmd -S MCLAUGHLINSQL\SQLEXPRESS -U student -P student -i C:\Data\MicrosoftSQL\sqltest.sql -o C:\Data\Microsoft\sqltest.out |
As always, I hope this helps.
Querying an Object Type
I demonstrated a number of SQL approaches to reading object types in Appendix B of the Oracle Database 12c PL/SQL Programming book. For example, the easiest one to construct and return the results from a TO_STRING member function uses the TREAT function:
SELECT TREAT(base_t() AS base_t).to_string() AS "Text" FROM dual; |
However, it seems that I could have provided one more. Here’s an example of how you can test the construction of an object type and how you can return its attributes with a query. It’s important to note that there’s a natural problem with this syntax when you increment a sequence inside the object type. The problem is that it double increments the counter for the sequence.
SELECT * FROM TABLE(SELECT CAST(COLLECT(base_t()) AS base_t_tab) FROM dual); |
The syntax for the COLLECT function requires that you put it inside a SELECT-list. Then, the CAST function converts a single instance of the BASE_T object type to a one element BASE_T_TAB collection. Finally, the TABLE function returns a single row from the BASE_T_TAB collection.
You can find a more complete article covering column substitutability and object types and subtypes on the ToadWorld site. I think it helps clear up how you can effectively write PL/SQL types and subtypes for persistent object type columns.
Finding Direct Indexes
If you’re not using Toad DBA Suite, it’s sometimes hard to find solutions. Somebody wanted to know how to find indexes that aren’t indirect. Indirect indexes are those created for a primary key because a primary key column or set of columns are both not null and uniquely constrained. Likewise, you create a unique index when you can create a unique constraint. You can’t drop a unique index for a primary key without dropping the primary key or unique constraint that indirectly created it.
The following query returns indexes with one or more columns that are created by a CREATE INDEX statement on a target table. It excludes unique indexes created by a primary key constraint, and it returns the relative position of columns in an index:
COLUMN sequence_name FORMAT A22 HEADING "Sequence Name" COLUMN column_position FORMAT 999 HEADING "Column|Position" COLUMN column_name FORMAT A22 HEADING "Column|Name" SELECT uin.index_name , uic.column_position , uic.column_name FROM user_indexes uin INNER JOIN user_ind_columns uic ON uin.index_name = uic.index_name AND uin.table_name = uic.table_name WHERE uin.table_name = UPPER('&&table_name') AND NOT uin.index_name IN (SELECT constraint_name FROM user_constraints WHERE table_name = UPPER('&&table_name')) ORDER BY uin.index_name , uic.column_position; |
It can be rewritten into a function, which can then drop indexes based on a table name:
CREATE OR REPLACE FUNCTION drop_indexes_on ( pv_table_name VARCHAR2 ) RETURN NUMBER IS /* A return value. */ lv_return NUMBER := 0; /* A query to return only directly created indexes. */ CURSOR find_indexes_on ( cv_table_name VARCHAR2 ) IS SELECT DISTINCT ui.index_name FROM user_indexes ui INNER JOIN user_ind_columns uic ON ui.index_name = uic.index_name AND ui.table_name = uic.table_name WHERE ui.table_name = UPPER(cv_table_name) AND NOT ui.index_name IN (SELECT constraint_name FROM user_constraints WHERE table_name = UPPER(cv_table_name)); /* Declare function autonomous. */ PRAGMA AUTONOMOUS_TRANSACTION; BEGIN /* Drop the indexes on a table. */ FOR i IN find_indexes_on(pv_table_name) LOOP EXECUTE IMMEDIATE 'DROP INDEX '||i.index_name; lv_return := 1; END LOOP; RETURN lv_return; END drop_indexes_on; / |
You can call the drop_on_indexes_on function like this:
SELECT drop_indexes_on(UPPER('address_lab')) FROM dual; |
Hope this helps those who need to work with dropping indexes.
E-Business Customers
It seems the Oracle E-Business Suite stymies newbies. Naturally, it’s complex and requires some research before you try to develop any customization.
Having recently fielded a question about how to manage, search, create and update customers for a third party order entry system, I’m always surprised by how little people know about Oracle’s Trading Community Architecture (TCA). They likewise frequently don’t know that there is already a documented process, like the one defined in the Oracle Trading Community Architecture User Guide:
You also have the Oracle Trading Community Architecture Reference Guide, which provides more detailed information. I strongly recommend you read these before trying to Google a solution that may or may not meet your needs. Naturally, good PL/SQL coding skills make this type of activity straightforward. That’s why Oracle staff should master PL/SQL.
Wrapping SQL*Plus
One annoying thing from installing Oracle Database 11g on Fedora, was that the up arrows for command history didn’t work. I decided to fix that today after seeing Lutz Hartmann’s article on rlwrap. Unfortunately, the epel (Extra Packages for Enterprise Linux) package he recommended doesn’t run on Fedora 20. You can read my tale of woe, or skip to the .bashrc function that fixed it when I installed only rlwrap.
Attempting it on yum, gave me these errors:
# yum install http://www.mirrorservice.org/sites/dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm Loaded plugins: langpacks, refresh-packagekit epel-release-6-8.noarch.rpm | 14 kB 00:00 Examining /var/tmp/yum-root-5CLTPa/epel-release-6-8.noarch.rpm: epel-release-6-8.noarch Marking /var/tmp/yum-root-5CLTPa/epel-release-6-8.noarch.rpm to be installed Resolving Dependencies --> Running transaction check ---> Package epel-release.noarch 0:6-8 will be installed --> Processing Conflict: epel-release-6-8.noarch conflicts fedora-release No package matched to upgrade: epel-release --> Finished Dependency Resolution Error: epel-release conflicts with fedora-release-20-3.noarch You could try using --skip-broken to work around the problem You could try running: rpm -Va --nofiles –nodigest |
Poking around for an epel fix wasn’t successful, so I chose to install only the rlwrap package. Here’s that command and log file:
[root@localhost ~]# yum install rlwrap Loaded plugins: langpacks, protectbase, refresh-packagekit 0 packages excluded due to repository protections Resolving Dependencies --> Running transaction check ---> Package rlwrap.x86_64 0:0.41-1.fc20 will be installed --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: rlwrap x86_64 0.41-1.fc20 updates 95 k Transaction Summary ================================================================================ Install 1 Package Total download size: 95 k Installed size: 204 k Is this ok [y/d/N]: y Downloading packages: rlwrap-0.41-1.fc20.x86_64.rpm | 95 kB 00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction (shutdown inhibited) Installing : rlwrap-0.41-1.fc20.x86_64 1/1 Verifying : rlwrap-0.41-1.fc20.x86_64 1/1 Installed: rlwrap.x86_64 0:0.41-1.fc20 Complete! |
The next step was getting it to work. A sqlplus function wrapper inside the .bashrc file seemed the easiest. Here’s the code to the .bashrc file:
# .bashrc # Source global definitions if [ -f /etc/bashrc ]; then . /etc/bashrc fi # Uncomment the following line if you don't like systemctl's auto-paging feature: # export SYSTEMD_PAGER= # 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. sqlplus() { if [ "$RLWRAP" = "0" ]; then sqlplus "$@" else rlwrap sqlplus "$@" fi } # Set vi as a command line editor. set -o vi |
As always, I hope this helps some folks.
Hiding a Java Source
The ability to deploy Java inside the Oracle database led somebody to conclude that the source isn’t visible in the data catalog. Then, that person found that they were wrong because the Java source is visible when you use a DDL command to CREATE, REPLACE, and COMPILE the Java source. This post discloses how to find the Java source and how to prevent it from being stored in the data catalog.
You can verify that the Java class and source files exist with the following query:
1 2 3 4 5 6 7 8 | COLUMN object_name FORMAT A20 HEADING "Object Name" COLUMN object_type FORMAT A12 HEADING "Object Type" COLUMN status FORMAT A14 HEADING "Object Status" SELECT object_name , object_type , status FROM user_objects WHERE object_name = 'ReadFile'; |
It displays:
Object Name Object Type Object Status -------------------- ------------ -------------- ReadFile JAVA SOURCE VALID ReadFile JAVA CLASS VALID 2 rows selected. |
Then, you can use the following query to discovery a Java library created by a SQL command:
1 2 3 4 5 6 | COLUMN line FORMAT 9999 HEADING "Line|#" COLUMN text FORMAT A66 HEADING "Text" SELECT line , text FROM user_source WHERE name = 'ReadFile'; |
It displays the following:
Line # Text ------- ------------------------------------------------------------------ 1 // Java library imports. 2 import java.io.File; 3 import java.io.BufferedReader; 4 import java.io.FileNotFoundException; 5 import java.io.IOException; 6 import java.io.FileReader; 7 import java.security.AccessControlException; 8 9 // Class definition. 10 public class ReadFile { 11 // Define class variables. 12 private static File file; 13 private static FileReader inTextFile; 14 private static BufferedReader inTextReader; 15 private static StringBuffer output = new StringBuffer(); 16 private static String outLine, outText; 17 18 // Define readText() method. 19 public static String readText(String fromFile) 20 throws AccessControlException, IOException { 21 // Read file. 22 try { 23 // Initialize File. 24 file = new File(fromFile); 25 26 // Check for valid file. 27 if (file.exists()) { 28 29 // Assign file to a stream. 30 inTextFile = new FileReader(file); 31 inTextReader = new BufferedReader(inTextFile); 32 33 // Read character-by-character. 34 while ((outLine = inTextReader.readLine()) != null) { 35 output.append(outLine + "\n"); } 36 37 // Assing the StringBuffer to a String. 38 outText = Integer.toString(output.toString().length()); 39 40 // Close File. 41 inTextFile.close(); } 42 else { 43 outText = new String("Empty"); }} 44 catch (IOException e) { 45 outText = new String(""); 46 return outText; } 47 return outText; }} 47 rows selected. |
You can eliminate the source by compiling the Java library outside the database. Then, you use the loadjava utility to load the only the class file into the data catalog. The syntax would be the following command for an importer user in a video Pluggable Database (PDB):
loadjava -r -f -o -user importer/importer@video ReadFile.class |
You should know that this syntax is disallowed by the loadjava utility, notwithstanding it’s found in the Oracle Database 12c documentation:
loadjava -r -f -o -user importer@video/importer ReadFile.class |
You can verify that only the Java class file exists with the following query:
1 2 3 4 5 6 7 8 | COLUMN object_name FORMAT A20 HEADING "Object Name" COLUMN object_type FORMAT A12 HEADING "Object Type" COLUMN status FORMAT A14 HEADING "Object Status" SELECT object_name , object_type , status FROM user_objects WHERE object_name = 'ReadFile'; |
It displays:
Object Name Object Type Object Status -------------------- ------------ -------------- ReadFile JAVA CLASS VALID 1 row selected. |
Hope this helps those who want to hide the Java source files.
External Table Access
I left to chance where students would attempt to place their external files in a Linux or Unix implementation. As frequently occurs, they choose a location in their student user’s home directory. Any attempt to read an external table based on a file in this type of directory fails because it’s not accessible by the Oracle user because the directory within the student user’s account isn’t reachable. You can’t simply chown a directory and the files in a directory.
The failure returns the following result:
SELECT COUNT(*) FROM transaction_upload * ERROR AT line 1: ORA-29913: error IN executing ODCIEXTTABLEOPEN callout ORA-29400: data cartridge error error opening FILE /home/student/upload/transaction_upload.LOG |
The reason isn’t readily visible to all, but a virtual directory must reference a physical directory owned by the oracle user and dba group. That also means the oracle user must own all directories from the logical mount point to the physical directory name.
Assuming you’re working in an Oracle Database 11g XE instance, you can create a valid upload directory by navigating to this directory:
/u01/app/oracle |
Then, issue this command as the root user to create a new upload directory:
mkdir upload |
Now you have the following directory:
/u01/app/oracle/upload |
Assuming you’ve created the upload directory as the root user, the root user should issue the following two commands from the /u01/app/oracle directory:
chown -R oracle:dba upload chmod -R 755 upload |
Having made that change you should now be able to query the external file source, like a *.csv (comma-separated values) file. Hope this helps those trying to use external tables, which I subsequently wrote about for Toad World – External Tables.
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