Data Type Mapping
When you move tables from an Oracle database to a TimesTen database, you observe some storage overhead because the two databases use different internal storage architectures.
As memory capacity is typically more constrained than disk capacity, minimize memory usage, especially when working with large volumes of data.
ttImportFromOracle maps Oracle column data types to compatible TimesTen data types that consume less memory, helping optimize memory usage. ttImportFromOracle maps numeric (NUMBER), variable-length (VARCHAR2 and NVARCHAR2), RAW, LONG, LONG RAW, and LOB (CLOB, NCLOB, and BLOB) data types to compatible TimesTen data types.
The following syntax shows that type mapping is controlled by the
–typeMap command line option:-typeMap num[,var[,rawlong[,lob[,tstz[,padding[,stats]]]]]]
The following table lists the supported Oracle data types and their default corresponding TimesTen data types:
| Oracle Data Type | TimesTen Data Type |
|---|---|
VARCHAR2
|
VARCHAR2
|
NVARCHAR2
|
NVARCHAR2
|
NUMBER
|
NUMBER
|
FLOAT
|
FLOAT
|
DATE
|
DATE
|
BINARY_FLOAT
|
BINARY_FLOAT
|
BINARY_DOUBLE
|
BINARY_DOUBLE
|
TIMESTAMP
|
TIMESTAMP
|
TIMESTAMP WITH TIME ZONE
|
TIMESTAMP
|
TIMESTAMP WITH LOCAL TIME ZONE
|
TIMESTAMP
|
CHAR
|
CHAR
|
NCHAR
|
NCHAR
|
CLOB
|
CLOB or VARCHAR2
|
NCLOB
|
NCLOB or NVARCHAR2
|
BLOB
|
BLOB or VARBINARY
|
RAW
|
VARBINARY
|
LONG
|
VARCHAR2
|
LONG RAW
|
VARBINARY
|
JSON
|
JSON
|