Appendix D. System Tables - D.31 RDB$RELATION_FIELDS - 《Firebird 4.0 Language Reference》

D.31 RDB$RELATION_FIELDS

D.31 `RDB$RELATION_FIELDS`

RDB$RELATION_FIELDS stores the definitions of table and view columns.

Column Name	Data Type	Description
`RDB$FIELD_NAME`	`CHAR(63)`	Column name
`RDB$RELATION_NAME`	`CHAR(63)`	The name of the table or view that the column belongs to
`RDB$FIELD_SOURCE`	`CHAR(63)`	Domain name on which the column is based, either a user-defined one specified in the table definition or one created automatically by the system using the set of attributes defined. The attributes are in the table `RDB$FIELDS`: this column matches `RDB$FIELDS.RDB$FIELD_NAME`.
`RDB$QUERY_NAME`	`CHAR(63)`	Not currently used
`RDB$BASE_FIELD`	`CHAR(63)`	Only populated for a view, it is the name of the column from the base table
`RDB$EDIT_STRING`	`VARCHAR(127)`	Not used
`RDB$FIELD_POSITION`	`SMALLINT`	The zero-based ordinal position of the column in the table or view, numbering from left to right
`RDB$QUERY_HEADER`	`BLOB TEXT`	Not used
`RDB$UPDATE_FLAG`	`SMALLINT`	Indicates whether the column is a regular one (value 1) or a computed one (value 0)
`RDB$FIELD_ID`	`SMALLINT`	An ID assigned from `RDB$RELATIONS.RDB$FIELD_ID` at the time the column was added to the table or view. It should always be treated as transient
`RDB$VIEW_CONTEXT`	`SMALLINT`	For a view column, the internal identifier of the base table from which this field derives
`RDB$DESCRIPTION`	`BLOB TEXT`	Comments related to the table or view column
`RDB$DEFAULT_VALUE`	`BLOB BLR`	The value stored for the DEFAULT clause for this column, if there is one, written in binary language representation (BLR)
`RDB$SYSTEM_FLAG`	`SMALLINT`	Indicates whether the column is user-defined (value 0) or system-defined (value 1 or greater)
`RDB$SECURITY_CLASS`	`CHAR(63)`	May reference a security class defined in `RDB$SECURITY_CLASSES`, in order to apply access control limits to all users of this column
`RDB$COMPLEX_NAME`	`CHAR(63)`	Not used
`RDB$NULL_FLAG`	`SMALLINT`	Indicates whether the column is nullable (`NULL`) non-nullable (value 1)
`RDB$DEFAULT_SOURCE`	`BLOB TEXT`	The source text of the `DEFAULT` clause, if any
`RDB$COLLATION_ID`	`SMALLINT`	The identifier of the collation sequence in the character set for the column, if it is not the default collation
`RDB$GENERATOR_NAME`	`CHAR(63)`	Internal generator name for generating an identity value for the column.
`RDB$IDENTITY_TYPE`	`SMALLINT`	The identity type of the column `NULL` - not an identity column `0` - identity column, `GENERATED ALWAYS` `1` - identity column, `GENERATED BY DEFAULT`