Oracle 12c now comes with the Database Migration Assistant for Unicode (DMU) for migration of Unicode character sets.  This replaces DB Character Set Scanner (CSSCAN) and CASALTER utility which are both de-supported.  DMU guides DBA through entire migration and contains a verification mode for existing Unicode databases.  Validation method identifies problems with Unicode existing and gives solutions.

 

Database must meet the following to support DMU.

1. DB version must be 10.2.0.4, 10.2.0.5, 11.1.0.7, 11.2.0.1 or later.
2. Character set must be ASCII based.
3. DBMS_DUMA_INTERNAL must be installed.
4. Oracle Database Vault must be disabled to migrate.
5. Cannot be 12c PDB.
6. DB must be in read/write mode.

 

Feature of DMU:

1. Selective Conversion – DMU has the ability to only convert data needed at table and column levels.
2. Monitoring – GUI used to track progress.
3. Inline Conversion – Support inline conversion of database content.
4. Scheduling – Removal of old data can be scheduled for future maintenance period.

 

Before conversion process, DMU preforms an analysis of varchar2, char, long, and CLOB to determine if anything will corrupt the data during Unicode conversion, it checks for the following:

1. If results are changed from original value.
2. Conversion fits in length limit of column.
3. Conversion results fit in data type of column.
4. Each character if valid in the source character code.

 

Larry Catt

OCP