Type Mapping Statistics

During data analysis, the import process gathers various statistics about the data. If you want, the generated CreateTables.sql file includes the statistics as comments.

This is controlled by the stats field of the –typeMap command line option. The stats field accepts any one of the following values:

Values	Description
0	This is the default value. The generated CreateTables.sql file does not include the statistics as comments.
1	The generated CreateTables.sql file includes the statistics as comments.

Type mapping can save a substantial amount of memory, but the savings depend heavily on the schema and data. It also introduces some risk.

Standard numeric type mapping (num=1) is safe for moving data from Oracle to TimesTen. However, the native integer types in TimesTen can store values that exceed the range supported by the corresponding Oracle NUMBER columns (depending on their definitions). If you plan to insert or update data in the TimesTen database and then move it back to the Oracle database, ensure that the values remain within the range supported by the corresponding Oracle columns.

Aggressive type mapping (num=2 and/or var=1) carries a higher risk because subsequent inserts or updates to the Oracle database may produce values that exceed the sizes allocated for the corresponding columns in the TimesTen database. You can mitigate this risk by using the padding feature carefully and understanding the application data and how it is used.