## 51.56. `pg_transform`

The catalog `pg_transform` stores information about transforms, which are a mechanism to adapt data types to procedural languages. See CREATE TRANSFORM for more information.

Table 51.56. `pg_transform` Columns

Name | Type | References | Description
--- | --- | --- | ---
`trftype` | `oid` | ``pg_type`.oid` | OID of the data type this transform is for
`trflang` | `oid` | ``pg_language`.oid` | OID of the language this transform is for
`trffromsql` | `regproc` | ``pg_proc`.oid` | The OID of the function to use when converting the data type for input to the procedural language (e.g., function parameters). Zero is stored if this operation is not supported.
`trftosql` | `regproc` | ``pg_proc`.oid` | The OID of the function to use when converting output from the procedural language (e.g., return values) to the data type. Zero is stored if this operation is not supported.