Supported DDL operations for a CDC Replication Engine for Oracle databases

Although a wide array of DDL operations exist, the CDC Replication Engine for Oracle databases replicates only those that are related to tables and characteristics of tables; it does not replicate the larger context of the database.

Examples of the table-related DDL operations that the CDC Replication Engine for Oracle databases will replicate include:

  • Tables
  • Object grants
  • Comments
  • Indexes
  • Partitions and subpartitions
  • Constraints

The following table indicates the types of DDL changes that can be replicated by the CDC Replication Engine for Oracle databases.

Draft comment:
truncating tables? ****- TRUNCATE operations (truncate table, truncate partition - do we support truncating partitions?) will be treated as DML operations, not DDL (even though Oracle considers truncates to be DDL?) (especially an issue for Replicate DDL only option) (we ignore truncate partition) (we will treat truncate table like a clear in a static mapping) - Alter Table, Truncate Partition? treated as DDL or ignored?

Table 1. Supported DDL operations
Supported DDL operations
Adding tables Dropping tables Dropping columns
Adding columns with a default value Modifying columns (widening widths, precision or range) Modifying columns (shrinking widths, precision or range)
Setting columns to unused Dropping unused columns Adding primary key constraints
Dropping primary key constraints Adding foreign key constraints Dropping foreign key constraints
Adding unique constraints Dropping unique constraints Adding an overflow tablespace
Adding not null constraints Disabling not null constraints Adding check constraints
Dropping check constraints Adding compression Dropping compression
Adding partitions Dropping partitions Splitting partitions
Adding subpartitions Dropping subpartitions Adding comments on tables
Deleting comments on tables Adding comments on columns Deleting comments on columns
Enabling row movement Shrinking spaces Shrinking space checks
Encrypting columns Decrypting columns Changing column types
Moving partitions Modifying partition ranges Moving subpartitions
Modifying subpartition ranges Enabling primary key constraint non-validation Disabling primary key constraint non-validation
Enabling foreign key constraint non-validation Disabling foreign key constraint non-validation Enabling unique constraint non-validation
Disabling unique constraint non-validation Enabling null constraint non-validation Disabling null constraint non-validation
Enabling check constraint non-validation Disabling check constraint non-validation Altering tables (read only)
Altering tables (read write) Making constraints deferrable deferred (primary key) Making constraints deferrable initially immediate (primary key)
Changing column encodings Enabling triggers Disabling triggers
Enabling primary key constraint validation Disabling primary key constraint validation Enabling foreign key constraint validation
Disabling foreign key constraint validation Enabling unique constraint validation Disabling unique constraint validation
Enabling null constraint validation Disabling null constraint validation Enabling check constraint validation
Disabling check constraint validation Setting table parallel degree (alter table parallel <degree>) Adding supplemental log groups
Dropping supplemental log groups    
Note: CDC Replication will successfully replicate any of the supported types of DDL operations only if they don't depend on any specific characteristics of the database session producing them. For example, a DDL containing a DATE in a format that does not match the database default. In order to replicate such a DDL, a user exit is needed.

Examples of the table-related objects for which DDL replication is not supported by CDC Replication include:

  • Views
  • Synonyms
  • Triggers
  • Materialized views
  • Materialized view logs
  • Tables containing user-defined types

Examples of the database-related objects for which DDL replication is not supported by CDC Replication include:

  • Functions
  • Stored procedures
  • Packages
  • Java™ classes
  • Database links
  • Roles
  • Directories
  • Dimensions
  • Libraries
  • Profiles
  • Users
  • Sequences
  • Tablespaces
  • Schemas

The following DDL operations are not supported by CDC Replication:

  • RENAME
  • REORG
  • FLASHBACK TO BEFORE DROP

Please note that TRUNCATE TABLE operations will be considered DML operations by tables with Direct Mappings. TRUNCATE (ANY OBJECT) operations will be replicated as DDL operations for Rules-based tables.