The DATASET type transform groups are used to import and export DATASET data from a client system to the Teradata Database, and from Teradata Database to a client system.
You can specify which predefined transform group is used by default for a certain data type. The DATASET transform groups are based on the DATASET type instance storage format.
STORAGE FORMAT Avro transforms must meet the following requirements:
- Transform to/from BLOB using TD_DATASET_AVRO_BLOB (default).
The BLOB is composed of the UTF-8 encoded schema, null-terminated, followed by the binary-encoded Avro value.
- Transform to/from VARBYTE using TD_DATASET_AVRO_VARBYTE
The VARBYTE is composed of the UTF-8 encoded schema, null-terminated, followed by the binary-encoded Avro value.
- Transform to/from CLOB in the CSV value character set using TD_Dataset_CSV_CLOB.
The CLOB is composed of a CSV value. Specified optional schemas are not included.
- Transforms to/from VARCHAR in the character set of the CSV value using TD_Dataset_CSV_VARCHAR.
The VARCHAR is composed of a CSV value. Specified optional schemas are not included.
The required formats of these transforms are equivalent to those defined for the system-defined casts.
You can use the TRANSFORM option in the CREATE PROFILE/MODIFY PROFILE or CREATE USER/MODIFY USER statements to specify for a user the particular transform group that will be used for a given data type.
Use the SET TRANSFORM GROUP FOR TYPE statement to change the active transform group in the current session. You can use this statement multiple times for a data type to switch from one transform group to another within the session. If the logon user already has transform settings, the statement modifies the transform settings for the current session.
Transform Group Macros
You can use the following macros to find the transform group for a UDT (or CDT), or the transform group settings for a user, profile, or current session.
|SYSUDTLIB.HelpCurrentUserTransforms||Lists the transform group settings of the current logon user.|
|SYSUDTLIB.HelpCurrentSessionTransforms||Lists the transform group settings of the current session.|
|SYSUDTLIB.HelpUserTransforms(User)||Lists the transform group settings for a specific user.|
Lists the transform group settings of the current session for the specified UDT.
|SYSUDTLIB.HelpUDTTransform(User,UDT)||Lists the transform group for a UDT for a user.|
|SYSUDTLIB.HelpProfileTransforms(Profile)||Lists the transform group settings for a specific profile.|
|Lists the transform group for a UDT for a profile.|
For more information about these macros, see Teradata Vantage™ SQL Data Definition Language Syntax and Examples, B035-1144.