RDB$FIELDS

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RDB$FIELDS defines the characteristics of a column. Each domain or column has a corresponding row in RDB$FIELDS. Columns are added to tables by means of an entry in the RDB$RELATION_FIELDS table, which describes local characteristics.

For domains, RDB$FIELDS includes domain name, null status, and default values. SQL columns are defined in RDB$RELATION_FIELDS. For both domains and simple columns, RDB$RELATION_FIELDS can contain default and null status information.

Column name	Data Type	Length	Description
RDB$FIELD_NAME	CHAR	67	Unique name of a domain or system-assigned name for a column, starting with SQL<nnn>; the actual column names are stored in the RDB$FIELD_SOURCE column of RDB$RELATION_FIELDS.
RDB$QUERY_NAME	CHAR	67	Not used for SQL objects.
RDB$VALIDATION_BLR	BLOB		Not used for SQL objects.
RDB$VALIDATION_SOURCE	BLOB		Not used for SQL objects.
RDB$COMPUTED_BLR	BLOB		Subtype BLR; for computed columns, contains the BLR (Binary Language Representation) of the expression the database evaluates at the time of execution.
RDB$COMPUTED_SOURCE	BLOB		Subtype Text: For computed columns, contains the original CHAR source expression for the column.
RDB$DEFAULT_VALUE	BLOB		Stores default rule; subtype BLR.
RDB$DEFAULT_SOURCE	BLOB		Subtype Text; SQL description of a default value.
RDB$FIELD_LENGTH	SMALLINT		Length in bytes of the field this row defines: For CHAR, VARCHAR, and NCHAR data types, this is the maximum length of the field, and InterBase uses this length when creating indexes on columns. For non-CHAR related data types, the column lengths are: D_FLOAT - 8 DOUBLE - 8 DATE - 4 BLOB - 8 TIME - 4 INT64 - 8 SHORT - 2 LONG - 4 QUAD - 8 FLOAT - 4 TIMESTAMP - 8 BOOLEAN - 2
RDB$FIELD_PRECISION	SMALLINT		Stores the precision for numeric and decimal types.
RDB$FIELD_SCALE	SMALLINT		Stores negative scale for numeric and decimal types.
RDB$FIELD_TYPE	SMALLINT		Specifies the data type of the column being defined; changing the value of this column automatically changes the data type for all columns based on the column being defined. Valid values are: BLOB - 261 BLOB_ID - 45 BOOLEAN - 17 CHAR - 14 CSTRING - 40 D_FLOAT - 11 DOUBLE - 27 FLOAT - 10 INT64 - 16 INTEGER - 8 QUAD - 9 SMALLINT - 7 DATE - 12 (dialect 3 DATE) TIME - 13 TIMESTAMP - 35 VARCHAR - 37 Restrictions: The value of this column cannot be changed to or from BLOB. Non-numeric data causes a conversion error in a column changed from CHAR to numeric. Changing data from CHAR to numeric and back again adversely affects index performance; for best results, delete and re-create indexes when making this type of change.
RDB$FIELD_SUB_TYPE	SMALLINT		Used to distinguish types of Blobs, CHAR values, and integers. 1 If RDB$FIELD_TYPE is 261 (Blob), predefined subtypes can be: 0 - unspecified 1 - text 2 - BLR (Binary Language Representation) 3 - access control list 4 - reserved for future use 5 - encoded description of a table’s current metadata 6 - description of multi-database transaction that finished irregularly 2 If RDB$FIELD_TYPE is 14 (CHAR), columns can be: 0 - type is unspecified 1 - fixed BINARY data Corresponds to the RDB$FIELD_SUB_TYPE column in the RDB$COLLATIONS table. 3 If RDB$FIELD_TYPE is 7 (SMALLINT), 8 (INTEGER), or 16 (INT64), the original declaration was: 0 or NULL- RDB$FIELD_TYPE 1 - NUMERIC 2 - DECIMAL
RDB$MISSING_VALUE	BLOB		Not used for SQL objects.
RDB$MISSING_SOURCE	BLOB		Not used for SQL objects.
RDB$DESCRIPTION	BLOB		Subtype Text: Contains a user-written description of the column being defined.
RDB$SYSTEM_FLAG	SMALLINT		For system tables
RDB$QUERY_HEADER	BLOB		Not used for SQL objects.
RDB$SEGMENT_LENGTH	SMALLINT		Used for Blob columns only; a non-binding suggestion for the length of Blob buffers.
RDB$EDIT_STRING	VARCHAR	125	Not used for SQL objects.
RDB$EXTERNAL_LENGTH	SMALLINT		Length of the column as it exists in an external table; if the column is not in an external table, this value is 0.
RDB$EXTERNAL_SCALE	SMALLINT		Scale factor for an external column of an integer data type; the scale factor is the power of 10 by which the integer is multiplied.
RDB$EXTERNAL_TYPE	SMALLINT		Indicates the data type of the column as it exists in an external table; valid values are: BLOB - 261 BLOB_ID - 45 BOOLEAN - 17 CHAR - 14 CSTRING - 40 D_FLOAT - 11 DOUBLE - 27 FLOAT - 10 INT64 - 16 INTEGER - 8 QUAD - 9 SMALLINT - 7 DATE - 12 (dialect 3 DATE) TIME - 13 TIMESTAMP - 35 VARCHAR - 37
RDB$DIMENSIONS	SMALLINT		For an ARRAY data type, specifies the number of dimensions in the array; for a non-array column, the value is 0.
RDB$NULL_FLAG	SMALLINT		Indicates whether a column can contain a NULL value. Valid values are: Empty: Can contain NULL values. 1: Cannot contain NULL values.
RDB$CHARACTER_LENGTH	SMALLINT		Length in characters of the field this row defines: For CHAR, VARCHAR, and NCHAR data types, this is the quotient of RDB$FIELD_LENGTH divided by the number of bytes per character in the character set of the field. For other data types, this length value is not meaningful, and should be NULL.
RDB$COLLATION_ID	SMALLINT		Unique identifier for the collation sequence.
RDB$CHARACTER_SET_ID	SMALLINT		ID indicating character set for the character or Blob columns; joins to the CHARACTER_SET_ID column of the RDB$CHARACTER_SETS system table.
RDB$SUBSCRIBE_FLAG	SMALLINT	2	Indicates one or more subscriptions of the field.