Rules for Database Objects
When creating database objects in an Ingres Replicator environment, be aware of the following restrictions:
• Replicated table and columns names must each be identical in each database. For example, a table named emp in database A can only be replicated to the table emp in database B, not to the table employee.
• Table names cannot begin with ii or conflict with Ingres Replicator catalogs. For more information, see the appendix "Data Dictionary Tables."
• Tables cannot have column names that begin with _ii_.
• Table names cannot exceed 256 bytes in length.
• Column names cannot exceed 252 characters in length.
Note: If you plan to replicate into a gateway database, limit the table and column name lengths to the OpenSQL-recommended standard of 18 characters.
• Column names cannot be the same as the column names Ingres Replicator uses as parameters in database procedures or columns in the shadow table. These column names include table_no, sequence_no, sourcedb, cdds_no, transaction_id, trans_time, s_new_key. For more information, see the appendix "Data Dictionary Tables."
• Each table to be replicated must have a PRIMARY KEY or UNIQUE column(s), a UNIQUE primary storage structure or a UNIQUE secondary index on one or more columns (up to a maximum of 31 columns). The column or columns that are part of the unique storage structure or index cannot be defined as nullable.
• Columns defined as replicated keys must be designated not null not default.
• Total width of the columns to be replicated is limited by the overhead of the archive and shadow rows. The archive table adds 10 bytes to the base row. Therefore, if you are using a 4 KB page size, the maximum base table row width is 3978. The shadow table adds 55 bytes to the base table primary key columns. These limits are not applicable if long varchar or long byte data types are used. For more information, see the chapter “Calculating Disk Space” in the Database Administrator Guide.
• You can define up to 32,767 databases per replicated system.
• Replication of system catalogs is not supported.
• Abstract data type date is not supported for gateway targets on certain platforms. Check your product documentation for details.
• Abstract data type money is not supported for Enterprise Access targets because money is not an OpenSQL data type.
• Replication of tables with an identity column used as the replication key is not supported between full peer databases.
Ingres Replicator cannot replicate:
• User-Defined Data Types (UDTs).
• Tables with any of the following data types as the table key: float, money, system_maintained table_key, or system_maintained object_key.