D.19. RDB$INDEX_SEGMENTS

RDB$INDEX_SEGMENTS stores the segments (table columns) of indexes and their positions in the key. A separate row is stored for each column in an index.

Column NameData TypeDescription

RDB$INDEX_NAME

CHAR(31)

The name of the index this segment is related to. The master record is RDB$INDICES.RDB$INDEX_NAME.

RDB$FIELD_NAME

CHAR(31)

The name of a column belonging to the index, corresponding to an identifier for the table and that column in RDB$RELATION_FIELDS.RDB$FIELD_NAME

RDB$FIELD_POSITION

SMALLINT

The column position in the index. Positions are numbered left-to-right, starting at zero

RDB$STATISTICS

DOUBLE PRECISION

The last known (calculated) selectivity of this column in the index. The higher the number, the lower the selectivity.