2 SQL Developer: Migrating Third-Party Databases

2.2.1.1 How Migration Works

The components of SQL Developer work together to migrate a third-party database to an Oracle database. Figure 2-1, "SQL Developer Migration Architecture" shows how SQL Developer reads the information from the source database and creates the Oracle database schema objects. SQL Developer uses the information stored in the migration repository to migrate to the Oracle schema. You can make changes to the captured model or the converted model, or both, before migrating. The information in the converted model is used to complete the migration, that is, to generate the database objects in the destination Oracle schema.

Figure 2-1 SQL Developer Migration Architecture

2.2.1.2 Migration Implemented as SQL Developer Extensions

Migration support is implemented in SQL Developer as a set of extensions. If you want, you can disable migration support or support for migrating individual third-party databases.

To view the installed extensions, and to enable or disable individual extensions, click Tools, then Preferences, then Extensions. Note that SQL Developer ships which all extensions and third-party database "plugins" available at the time of release, so to begin migrations other than for Microsoft Access, only the third-party drivers need be installed.

2.2.2.1 Task 1: Determining the Requirements of the Migration Project

In this task, you identify which databases you want to migrate and applications that access that database. You also evaluate the business requirements and define testing criteria.

To determine the requirements of the migration project:

1. Define the scope of the project.

   There are several choices you must make about the third-party database and applications that access that database in order to define the scope of the migration project. To obtain a list of migration issues and dependencies, you should consider the following

   • What third-party databases are you migrating?

     • What is the version of the third-party database?

     • What is the character set of the third-party database?

   • What source applications are affected by migrating the third-party database to an Oracle database?

     • What is the third-party application language?

     • What version of the application language are you using?

     In the scope of the project, you should have identified the applications you must migrate. Ensure that you have included all the necessary applications that are affected by migrating the database

   • What types of connectivity issues are involved in migrating to an Oracle database?

     • Do you use connectivity software to connect the applications to the third-party database? Do you need to modify the connectivity software to connect the applications to the Oracle database?

     • What version of the connectivity software do you use? Can you use this same version to connect to the Oracle database?

   • Are you planning to rewrite the applications or modify the applications to work with an Oracle database?

2. Use Table 2-1 to determine whether you have a complex or simple source database environment. Identify the requirements based on the specific scenario.

   If the migration project is a simple scenario, you may not have to complete all possible migration tasks. You make decisions based on your specific environment. For example, if you have a complex scenario, you may require extra testing based on the complexity of the application accessing the database.

   Table 2-1 Complex and Simple Scenarios

   Complex Scenario	Simple Scenario
   Involves more than one of the following: Large database (greater than 25 GB) Data warehouse Large applications (more than 100 forms, reports, and batch jobs) Database used by multiple lines of business Distributed deployment Large user base (more than 100) High availability requirement (such as a 24 X 7 X 365 environment)	Involves the following: Small database (less than 25 GB) Simple online transaction processing (OLTP) Small application (less than 100 forms, reports, and batch jobs) Database used by one department Centralized deployment Small user base (less than 100) Average availability (business hours)

   
   

3. Determine whether the destination database requires additional hardware and rewriting of backup schedules.

4. Define testing and acceptance criteria.

   Define tests to measure the accuracy of the migration. You then use the acceptance criteria to determine whether the migration was successful. The tests that you develop from the requirements should also measure stability, evaluate performance, and test the applications. You must decide how much testing is necessary before you can deploy the Oracle database and applications into a production environment.

5. Create a requirements document with a list of requirements for the migration project.

   The requirements document should have clearly defined tasks and number each specific requirement, breaking these into sub-requirements where necessary.

2.2.2.2 Task 2: Estimating Workload

In this task, you use SQL Developer to make calculated decisions on the amount of work that can be automated and how much is manual.

To estimate the workload:

1. Capture the captured model, create the converted model, and migrate to the destination database.

   You can analyze the source database through the captured model and a preview of the destination database through the converted model. After you have captured the source database, analyze the captured data contained in the captured model and the converted model. Ensure the content and structure of the migration repository is correct and determine how much time the entire process takes.

2. Use the Migration Log pane to evaluate the capture and migration process, categorize the total number of database objects, and identify the number of objects that can be converted and migrated automatically.

   The migration log provides information about the actions that have occurred and record any warnings and errors. They identify the changes that have been made to the converted model so that you can evaluate if you should make changes to the applications that access the destination database.

3. Evaluate and categorize the issues that occurred. The migration log can help by providing information about:

   • Tables that did not load when you captured the source database

   • Stored procedures, views, and triggers that did not parse when you created the converted model

   • Syntax that requires manual intervention

   • Database objects that were not created successfully when you migrated the destination database

   • Data that did not migrate successfully when you migrated the destination database

4. For each error or warning in the migration log, evaluate the following:

   • Number of times an issue occurred

   • Time required to fix the issues, in person-hours

   • Number of resources required to fix the issue

     After you have solved a complex problem, it should be easier and quicker to resolve the next time you have the same problem.

2.2.2.3 Task 3: Analyzing Operational Requirements

In this task, you analyze the operational requirements, as follows:

1. Evaluate the operational considerations in migrating the source database to a destination database. Consider the following questions:

   Note:

   If the scope of the migration project is a complex scenario as defined in Table 2-1, Oracle recommends that you answer all of these questions. If you have a simple scenario, determine the answers to the most appropriate questions.

   • What backup and recovery changes do you require?

   • What downtime is required during the migration?

   • Have you met the performance requirements?

   • Are you changing the operational time window?

   • What effect does the downtime have on the business?

   • What training requirements or additional staff considerations are required?

   • Is it necessary to have the third-party and the Oracle database running simultaneously?

2. For each task, determine the resources and time required to complete.

3. Create an initial project plan.

   Use the information that you have gathered during the requirements and planning stage to develop an initial project plan.

2.2.2.4 Task 4: Analyzing the Application

In this task, you identify the users of the applications that run on the source database, what hardware it requires, what the application does, and how it interfaces with the source database. You also analyze the method the application uses to connect to the database and identify necessary modifications.

To analyze the application:

1. Determine whether changes to the application are required to make them run effectively on the destination database.

2. If changes are required to the application, determine whether it is more efficient to rewrite or modify the applications.

   If you are rewriting the application to use the Oracle database, consider the following:

   1. Create the necessary project documentation to rewrite the application. For example, you need a design specification and requirements documentation.

   2. Rewrite the application according to the specification.

   3. Test the application works against the Oracle database.

   If you are modifying the application to use the Oracle database, consider the following:

   1. Identify the number of connections to the database that are in the application and modify these connections to use the Oracle database.

      You may need to change the connection information to use an ODBC or JDBC connection.

   2. Identify the embedded SQL statements that you need to change in the application before you can test it against the Oracle database.

   3. Test the application using the Oracle database.

3. Allocate time and resource to address each issue associated with rewriting or modifying the application.

4. Update the general requirements document for the project that you created in Task 1.

2.2.2.5 Task 5: Planning the Migration Project

In this task, you evaluate the unknown variables that the migration project may contain, such as the difference in the technologies of the source database and the destination database. During the planning stage, you:

• Estimate the budget constraints of the project

• Gather information to produce a migration plan

• Estimate how much time the migration project should take

• Calculate how many resources are required to complete and test the migration

To plan a migration project:

1. Define a list of tasks required to successfully complete the migration project requirements of Task 1.

2. Categorize the list of tasks required to complete the migration project.

   You should group these tasks according to your business. This allows you to schedule and assign resources more accurately.

3. Update and finalize the migration project plan based on the information that you have obtained from Task 3 and Task 4.

4. Make sure the migration project plan meets the requirements of the migration project.

   The migration plan should include a project description, resources allocated, training requirements, migration deliverable, general requirements, environment analysis, risk analysis, application evaluation, and project schedule.

2.2.3.1 Creating a Database User for the Migration Repository

SQL Developer requires a migration repository to migrate a third-party database to an Oracle database. To use an Oracle database for the migration repository, you must have access to that database using a database user account. Oracle recommends that you use a specific user account for migrations, For example, you may want to create a user named MIGRATIONS, create a database connection to that user, and use that connection for the migration repository; and if you wish, you can later delete the MIGRATIONS user to remove all traces of the migration from the database.

When you create a user for migrations, specify the tablespace information as in the following example, instead of using the defaults for tablespaces:

CREATE USER migrations IDENTIFIED BY <password>
  DEFAULT TABLESPACE users TEMPORARY TABLESPACE temp,

Do not use a standard account (for example, SYSTEM) for migration.

When SQL Developer creates a migration repository, it creates many schema objects that are intended only for its own use. For example, it creates tables, views, indexes, packages, and triggers, many with names starting with MD_ and MIGR. You should not directly modify these objects or any data stored in them.

2.2.3.2 Requirements for Creating the Destination Oracle Objects

The user associated with the Oracle database connection used to perform the migration (that is, to run the script containing the generated DDL statements) must have the following roles and privileges:

Roles

CONNECT WITH ADMIN OPTION
RESOURCE WITH ADMIN OPTION

Privileges

ALTER ANY ROLE
ALTER ANY SEQUENCE
ALTER ANY TABLE
ALTER TABLESPACE
ALTER ANY TRIGGER
COMMENT ANY TABLE
CREATE ANY SEQUENCE
CREATE ANY TABLE
CREATE ANY TRIGGER
CREATE VIEW WITH ADMIN OPTION
CREATE PUBLIC SYNONYM WITH ADMIN OPTION
CREATE ROLE
CREATE USER
DROP ANY SEQUENCE
DROP ANY TABLE
DROP ANY TRIGGER
DROP USER
DROP ANY ROLE
GRANT ANY ROLE
INSERT ANY TABLE
SELECT ANY TABLE
UPDATE ANY TABLE

For example, you can create a user called migrations with the minimum required privileges required to migrate a database by using the following commands:

CREATE USER migrations IDENTIFIED BY password
  DEFAULT TABLESPACE users TEMPORARY TABLESPACE temp;
 
GRANT CONNECT, RESOURCE, CREATE VIEW, CREATE PUBLIC SYNONYM TO 
  migrations WITH ADMIN OPTION;
 
GRANT  ALTER ANY ROLE, ALTER ANY SEQUENCE, ALTER ANY TABLE, ALTER TABLESPACE,
ALTER ANY TRIGGER, COMMENT ANY TABLE, CREATE ANY SEQUENCE, CREATE ANY TABLE,
CREATE ANY TRIGGER, CREATE ROLE, CREATE TABLESPACE, CREATE USER, DROP ANY
SEQUENCE, DROP ANY TABLE, DROP ANY TRIGGER, DROP TABLESPACE, DROP USER, DROP ANY
ROLE, GRANT ANY ROLE, INSERT ANY TABLE, SELECT ANY TABLE, UPDATE ANY TABLE TO 
migrations;

After you have created the converted model and done first DDL generation done for the new database, it will be clear from the scripts which privileges will be required for your situation.

2.2.4.1 Before Migrating From IBM DB2

To configure an IBM DB2 database for migration:

1. Ensure that the source database is accessible by the IBM DB2 database user that is used by SQL Developer for the source connection. This user must be able to see any objects to be captured in the IBM DB2 database; objects that the user cannot see are not captured. For example, if the user can execute a stored procedure but does not have sufficient privileges to see the source code, the stored procedure cannot be captured.

2. Ensure that you can connect to the IBM DB2 database from the system where you have installed SQL Developer.

3. Ensure that you have downloaded the db2jcc.jar and db2jcc_license_cu.jar files from IBM.

4. In SQL Developer, do the following:

   1. Click Tools, then Preferences, then Database, then Third Party JDBC Drivers.

   2. Click Add Entry.

   3. Select the db2jcc.jar file.

   4. Click OK.

   5. Repeat steps b through d for the db2jcc_license_cu.jar file.

2.2.4.2 Before Migrating From Microsoft SQL Server or Sybase Adaptive Server

To configure a Microsoft SQL Server or Sybase Adaptive Server database for migration:

1. Ensure that the source database is accessible by the Microsoft SQL Server or Sybase Adaptive Server user that is used by SQL Developer for the source connection. This user must be able to see any objects to be captured in the Microsoft SQL Server or Sybase Adaptive Server database; objects that the user cannot see are not captured. For example, if the user can execute a stored procedure but does not have sufficient privileges to see the source code, the stored procedure cannot be captured.

2. Ensure that you can connect to the Microsoft SQL Server or Sybase Adaptive Server database from the system where you have installed SQL Developer.

3. Ensure that you have downloaded the JTDS JDBC driver from http://jtds.sourceforge.net/.

4. In SQL Developer, if you have not already installed the JTDS driver using Check for Updates (on the Help menu), do the following:

   1. Click Tools, then Preferences, then Database, then Third Party JDBC Drivers.

   2. Click Add Entry.

   3. Select the jar file for the JTDS driver you downloaded from http://jtds.sourceforge.net/.

   4. Click OK.

5. In SQL Developer, click Tools, then Preferences, then Migration: Identifier Options, and ensure that the setting is correct for the Is Quoted Identifier On option (that is, that the setting reflects the database to be migrated).

   If this option is enabled, quotation marks (double-quotes) can be used to refer to identifiers; if this option is not enabled, quotation marks identify string literals. As an example of the difference in behavior, consider the following T-SQL code:

   select col1, "col 2" "column_alias"
   from tablex "table_alias"
   

   If the Is Quoted Identifier On option is enabled (checked), the following PL/SQL code is generated:

   SELECT col1, col_2 "column_alias"
     FROM tablex "table_alias";
   

   If the Is Quoted Identifier On option is disabled (not checked), the following PL/SQL code is generated:

   SELECT col1, 'col 2' "column_alias"
     FROM tablex "table_alias";
   

2.2.4.3 Before Migrating From Microsoft Access

To configure a Microsoft Access database for migration:

1. Make backup copies of the database file or files.

2. Ensure that the necessary software (Microsoft Access, perhaps other components) is installed on the same system as SQL Developer.

3. Ensure that the Admin user has at least Read Design and Read Data permissions on the MSysObjects, MSysQueries, and MSysRelationships system tables, as explained in the information about the Access tab in the Create/Edit/Select Database Connection dialog box.

4. If security is enabled, you should turn it off by copying the contents of the secured database into a new database, as follows:

   SQL Developer does not support the migration of Microsoft Access databases that have security enabled. By default, SQL Developer uses the name of the Microsoft Access MDB file as the user name for the destination Oracle user. If you create an Oracle user in this way, the password is ORACLE.

   1. From the File menu in Microsoft Access, select New Database.

   2. Select the Blank Database icon, then click OK.

   3. In the File New Database option, type a name for the database, then click Create.

   4. From the File menu within the new database, select Get External Data, then select Import.

   5. Select the secured Microsoft Access database that you want to import, then click Import.

   6. From the Import Objects dialog, click Options.

   7. Select the Relationships and Definition and Data options.

   8. From the Tables tab, choose Select All.

   9. Click OK.

      All Microsoft Access objects are copied over to the new Microsoft Access database, except for the security settings.

5. If the application contains linked tables to other Microsoft Access databases, refresh these links by opening the application in Microsoft Access and performing the following:

   From the Tools menu in Microsoft Access 97, select Add Ins, then select Linked Table Manager.

   From the Tools menu in Microsoft Access 2000, select Database Utilities, then select Linked Table Manager.

6. Ensure that the Microsoft Access database is not a replica database, but a master database.

   When you use the Exporter for Microsoft Access to export, an error message is displayed if the database is a replica. SQL Developer does not support the migration of a replica database.

7. From the Tools menu within Microsoft Access, select Database, then select Compact Database to compact the Microsoft Access database files.

8. Ensure that the Microsoft Access database file is accessible from the system where you have installed SQL Developer.

9. Use the Oracle Universal Installer to verify that you have the Oracle ODBC driver installed. If you need to install the driver, it is available on the Oracle Database Server or Database Client CD. You can also download the Oracle ODBC driver from the Oracle Technology Network (OTN) website:

   http://www.oracle.com/technetwork/developer-tools/visual-studio/downloads/
   

   Install the Oracle ODBC driver into an Oracle home directory that contains the Oracle Net Services. You can obtain the Oracle Net Services from the Oracle Client or Oracle Database CD. You install Oracle Net Services to obtain the Net Configuration Assistant and Net Manager. These allow you to create a net configuration in the tnsnames.ora file.

   Note:

   For more information about installing the networking products needed to connect to an Oracle database, see the installation guide for your Oracle Database release.

2.2.4.4 Before Migrating From MySQL

To configure a MySQL database for migration, install MySQLConnector/J release 3.1.12 or 5.0.4 on the system where you have installed SQL Developer and set the appropriate SQL Developer preference. Follow these steps:

1. Ensure that you can connect to the MySQL database from the system where you have installed SQL Developer.

2. Ensure that you have downloaded the MySQLConnector/J API from the MySQL website at http://www.mysql.com/.

3. In SQL Developer, if you have not already installed the MySQL JDBC driver using Check for Updates (on the Help menu), do the following:

   1. Click Tools, then Preferences, then Database, then Third Party JDBC Drivers.

   2. Click Add Entry.

   3. Select the jar file for the MySQL driver you downloaded from http://www.mysql.com/.

   4. Click OK.

4. Ensure that the source database is accessible by the MySQL user that is used by SQL Developer for the source connection. This user must be able to see any objects to be captured in the MySQL database; objects that the user cannot see are not captured. For example, if the user can execute a stored procedure but does not have sufficient privileges to see the source code, the stored procedure cannot be captured.

2.2.4.5 Before Migrating From Teradata

Note that for the current release of SQL Developer, the following Teradata objects will not be migrated to Oracle: procedures, functions, triggers, views, macros, and BTEQ scripts.

To configure a Teradata database for migration:

1. Ensure that the source database is accessible by the Teradata database user that is used by SQL Developer for the source connection. This user must be able to see any objects to be captured in the Teradata database; objects that the user cannot see are not captured.

2. Ensure that you can connect to the Teradata database from the system where you have installed SQL Developer.

3. Ensure that you have downloaded the tdgssconfig.jar and terajdbc4.jar files from Teradata.

4. In SQL Developer, do the following:

   1. Click Tools, then Preferences, then Database, then Third Party JDBC Drivers.

   2. Click Add Entry.

   3. Select the tdgssconfig.jar file.

   4. Click OK.

   5. Repeat steps b through d for the terajdbc4.jar file.

2.2.5.1 Offline Capture

To perform an offline capture of an IBM DB2, MySQL, Microsoft SQL Server, or Sybase Adaptive Server database, you create a set of offline capture scripts, run these scripts outside SQL Developer to create the script output (a dump of the third party metadata tables), and load the script output (the .ocp file containing the converted model) using SQL Developer.

• To create the script file (a Windows .bat file or a Linux or UNIX .sh file) and related files, click Tools, then Migration, then Create Database Capture Scripts.

  When this operation completes, you are notified that several files (.bat, .sql, .ocp) have been created, one of which is the controlling script. You must run the controlling script (outside SQL Developer) to populate the object capture properties (.ocp) file with information about the converted model.

• To load the converted model from the object capture properties (.ocp) file generated by the offline capture controlling script, click Tools, then Migration, then Third Party Database Offline Capture, then Load Database Capture Script Output.

db2 -x +o -r <file name> <schema query>

db2 connect to <catalog> user <user name> using <password>

2.2.6.1 Correcting Errors in the Converted Model

If error messages with the prefix Parse Exception are listed in the migration log, manual intervention is required to resolve the issues. To complete the converted model:

1. Note the converted model schema object that failed.

2. Select that schema object in the converted model.

3. Copy the schema objects DDL and paste it into the translation scratch editor (displayed by clicking Migration, then Translation Scratch Editor).

4. Inspect the properties on the schema object in the translation scratch editor for possible causes of the error.

5. Modify a property of the schema object in the translation scratch editor.

   For example, you might comment out one line of a stored procedure.

6. Translate using the appropriate translator.

7. If the error appears again, repeat steps 2 to 6.

8. If the error cannot be resolved in this way, it is best to modify the object manually in the converted model.

2.2.8.1 Transferring the Data Offline

To transfer the data offline, you generate and use scripts to copy data from the source database to the destination database. During this process you must:

• Use SQL Developer to generate the data unload scripts for the source database and corresponding data load scripts for the destination database.

• Run the data unload scripts to create data files from the source database using the appropriate procedure for your source database:

  • Creating Data Files From Microsoft SQL Server or Sybase Adaptive Server

  • Creating Data Files From Microsoft Access

  • Creating Data Files From MySQL

  • For IBM DB2, see the chapter about offline data loading in Oracle SQL Developer Supplementary Information for IBM DB2 Migrations.

  • For Teradata, perform the offline data move using BTEQ and SQL*Loader.

• Run the data load scripts using SQL*Loader to populate the destination database with the data from these data files as described in Section 2.2.8.1.4.

SQL*Loader-309: No SQL string allowed as part of LARGEOBJECT field specification

<blob_column> CHAR(2000000) "HEXTORAW (:<blob_column>)"

<blob_column>_CLOB CHAR(2000000)

-- START.SQL
-- Modify this for your environment.
 
-- This should be executed in the user schema in Oracle that contains the table.
-- DESCRIPTION:
-- ALTERS THE OFFENDING TABLE SO THAT THE DATA MOVE CAN BE EXECUTED
-- DISABLES TRIGGERS, INDEXES AND SEQUENCES ON THE OFFENDING TABLE
 
-- 1) Add an extra column to hold the hex string;
alter table <tablename> add (<blob_column>_CLOB CLOB);
 
-- 2) Allow the BLOB column to accept NULLS
alter table <tablename> MODIFY <blob_column> NULL;
 
-- 3) Disable triggers and sequences on <tablename>
alter trigger <triggername> disable;
 
alter table <tablename> drop primary key cascade;
 
drop index <indexname>;
 
-- 4) Allow the table to use the tablespace
alter table <tablename> move lob (<blob_column>) store as (tablespace lob_tablespace);
 
alter table <tablename> move lob (<blob_column>_clob) store as (tablespace lob_tablespace);
 
COMMIT;
 
-- END OF FILE
 
 
-- FINISH.SQL
-- Modify this for your enironment.
 
-- This should be executed in the table schema in Oracle.
-- DESCRIPTION:
-- MOVES THE DATA FROM CLOB TO BLOB
-- MODIFIES THE TABLE BACK TO ITS ORIGINAL SPEC (without a clob)
-- THEN ENABLES THE SEQUENCES, TRIGGERS AND INDEXES AGAIN
 
-- Currently we have the hex values saved as 
-- text in the <blob_column>_CLOB column
-- And we have NULL in all rows for the <blob_column> column.
-- We have to get BLOB locators for each row in the BLOB column
 
-- put empty blobs in the blob column
UPDATE <tablename> SET <blob_column>=EMPTY_BLOB();
 
COMMIT;
 
-- create the following procedure in your table schema
CREATE OR REPLACE PROCEDURE CLOBTOBLOB
AS
inputLength NUMBER; -- size of input CLOB
offSet NUMBER := 1;
pieceMaxSize NUMBER := 2000; -- the max size of each peice
piece VARCHAR2(2000); -- these pieces will make up the entire CLOB
currentPlace NUMBER := 1; -- this is where were up to in the CLOB
blobLoc BLOB; -- blob locator in the table
clobLoc CLOB; -- clob locator pointsthis is the value from the dat file
 
-- THIS HAS TO BE CHANGED FOR SPECIFIC CUSTOMER TABLE 
-- AND COLUMN NAMES
CURSOR cur IS SELECT <blob_column>_clob clob_column , <blob_column> blob_column FROM /*table*/<tablename> FOR UPDATE;
 
cur_rec cur%ROWTYPE;
 
BEGIN
 
OPEN cur;
FETCH cur INTO cur_rec;
 
WHILE cur%FOUND
LOOP
--RETRIVE THE clobLoc and blobLoc
clobLoc := cur_rec.clob_column;
blobLoc := cur_rec.blob_column;
 
currentPlace := 1; -- reset evertime
-- find the lenght of the clob
inputLength := DBMS_LOB.getLength(clobLoc);
 
-- loop through each peice
LOOP
-- get the next piece and add it to the clob
piece := DBMS_LOB.subStr(clobLoc,pieceMaxSize,currentPlace);
 
-- append this piece to the BLOB
DBMS_LOB.WRITEAPPEND(blobLoc, LENGTH(piece)/2, HEXTORAW(piece));
 
currentPlace := currentPlace + pieceMaxSize ;
 
EXIT WHEN inputLength < currentplace;
END LOOP;
 
FETCH cur INTO cur_rec;
END LOOP;
 
END CLOBtoBLOB;
/
 
-- now run the procedure
-- It will update the blob column with the correct binary representation
-- of the clob column
EXEC CLOBtoBLOB;
 
-- drop the extra clob cloumn
alter table <tablename> drop column <blob_column>_clob;
 
-- 2) apply the constraint we removed during the data load
alter table <tablename> MODIFY FILEBINARY NOT NULL;
 
-- Now re enable the triggers, indexes and primary keys
alter trigger <triggername> enable;
 
ALTER TABLE <tablename> ADD ( CONSTRAINT <pkname> PRIMARY KEY ( <column>) ) ;
 
CREATE INDEX <index_name> ON <tablename>( <column> );
 
COMMIT;
 
-- END OF FILE

2.2.10.1 Testing Methodology

Many constraints shape the style and amount of testing that you perform on a database. Testing can contain one or all of the following:

• Simple data validation

• Full life cycle of testing addressing individual unit tests

• System and acceptance testing

You should follow a strategy for testing that suits your organization and circumstances. Your strategy should define the process by which you test the migrated application and Oracle database. A typical test method is the V-model, which is a staged approach where each feature of the database creation is mirrored with a testing phase.

Figure 2-2, "V-model with a Database Migration" shows an example of the V-model with a database migration scenario:

Figure 2-2 V-model with a Database Migration

Description of "Figure 2-2 V-model with a Database Migration"

There are several types of tests that you use during the migration process. During the testing stage, you go through several cycles of testing to enhance the quality of the database. The test cases you use should make sure that any issues encountered in a previous version of the Oracle database are not introduced again.

For example, if you have to make changes to the migrated schema based on test results, you may need to create a new version of the Oracle database schema. In practice, you use SQL Developer to create a base-line Oracle schema at the start of testing, and then edit this schema as you progress with testing.

2.2.10.2 Testing the Oracle Database

Use the test cases to verify that the Oracle database provides the same business logic results as the source database.

This procedure explains one way of testing the migrated database. Other methods are available and may be more appropriate to your business requirements.

To test the Oracle database:

1. Create a controlled version of the migrated database.

   Oracle recommends that you keep the database migration scripts in a source control system.

2. Design a set of test cases that you can use to test the Oracle database from unit to system level. The test cases should:

   1. Ensure the following:

      • All the users in the source database have migrated successfully

      • Privileges and grants for users are correct

      • Tables have the correct structure, defaults are functioning correctly, and errors did not occur during mapping or generation

   2. Validate that the data migrated successfully by doing the following:

      • Comparing the number of rows in the Oracle database with those in the source database

      • Calculating the sum of numerical columns in the Oracle database and compare with those in the source database

   3. Ensure that the following applies to constraints:

      • You cannot enter duplicate primary keys

      • Foreign keys prevent you from entering inconsistent data

      • Check constraints prevent you from entering invalid data

   4. Check that indexes and sequences are created successfully.

   5. Ensure that views migrated successfully by doing the following:

      • Comparing the number of rows in the Oracle database with those in the source database

      • Calculating the sum of numerical columns in the Oracle database and compare with those in the source database

   6. Ensure that triggers, procedures, and functions are migrated successfully. Check that the correct values are returned for triggers and functions.

3. Run the test cases against the migrated database.

4. Create a report that evaluates the test case results.

   These reports allow you to evaluate the data to qualify the errors, file problem reports, and provide a customer with a controlled version of the database.

5. If the tests pass, go to step 7.

   If all tests in the test cases pass or contain acceptable errors, the test passes. If acceptable errors occur, document them in an error report that you can use for audit purposes.

6. If the test cases fail:

   1. Identify the cause of the error.

   2. Identify the test cases needed to check the errors.

   3. Log an issue on the controlled version of the migrated database code in the problem report.

   4. Add the test case and a description of the problem to the incident tracking system of your organization, which could be a spreadsheet or bug reporting system. Aside from the test case, the incident log should include the following:

      • Provide a clear, concise description of the incident encountered

      • Provide a complete description of the environment, such as platform and source control version

      • Attach the output of the test, if useful

      • Indicate the frequency and predictability of the incident

      • Provide a sequence of events leading to the incident

      • Describe the effect on the current test, diagnostic steps taken, and results noted

      • Describe the persistent after effect, if any

   5. Attempt to fix the errors.

   6. Return to step 1.

7. Identify acceptance tests that you can use to make sure the Oracle database is an acceptable quality level.

select count(*) from emp

select count(*) from emp

select sum(salary) from emp

select sum(salary) from emp

2.2.11.1 Choosing a Rollout Strategy

The strategy that you use for migrating a third-party database to an Oracle database must take into consideration the users and the type of business that may be affected during the transition period. For example, you may use the Big Bang approach because you do not have enough systems to run the source database and Oracle database simultaneously. Otherwise, you may want to use the Phased approach to make sure that the system is operating in the user environment correctly before it is released to the general user population. You can use one of the following approaches.

2.2.11.2 Deploying the Destination Database

There are several ways to deploy the destination database. The following task is an example that you should use as a guideline for deploying the destination database.

1. Configure the hardware, if necessary.

   In a large scale or complex environment, you must design the disk layout to correspond with the database design. If you use redundant disks, align them in stripes that you can increase as the destination database evolves. You must install and configure the necessary disks, check the memory, and configure the system.

2. Make sure the operating system meets the parameters of the Oracle configuration.

   Before installing any Oracle software, make sure that you have modified all system parameters. For more information about modifying system parameters, see the relevant installation guide for your platform, such as Solaris Operating System.

3. Install the Oracle software.

   Aside from the Oracle software that allows you to create an Oracle database, you may need to install ancillary software to support the application, such as Extract Transformation and Load (ETL) Software for data warehousing.

4. Create the destination database from the source database and migrate the data to the Oracle database.

   There are several ways of putting the destination database into production after testing it, such as:

   • Place the successfully tested database into production. The test system is now the production system.

   • Use Oracle Export to extract the destination database from the successfully tested database and use Oracle Import to create that database within the production environment.

   • Use the tested migration scripts to create the Oracle database and populate it with data using SQL*Loader.

5. Perform the final checks on the destination database and applications.

6. Place the destination database into production using one of the rollout strategies.

7. Perform a final audit by doing the following:

   • Audit the integrity of the data

   • Audit the validity of the processes, such as back-up and recovery

   • Obtain sign-off for the project, if necessary