The RDB$FIELDS system table describes the global (generic)
characteristics of each domain in the database. There is one
row for each domain in the database. The following table provides
information on the columns of the RDB$FIELDS system table.
Data
Column Name Type Summary Description
RDB$FIELD_NAME char(31) The name of the domain
represented by this row.
Each row within
RDB$FIELDS must have a
unique
RDB$FIELD_NAME value.
RDB$FIELD_TYPE integer The data type of the domain
represented by this row.
This data type must be
interpreted according to
the rules for interpreting
the DSC$B_DTYPE field of
class S descriptors (as
defined in the OpenVMS
Calling Standard).
Segmented strings require
a unique field type
identifier. This identifier
is 261.
RDB$FIELD_LENGTH integer The length of the field
represented by this
row. This length must be
interpreted according to
the rules for interpreting
the DSC$W_LENGTH field
within class S and SD
descriptors (as defined in
OpenVMS Calling Standard).
For strings, this field
contains the length in
octets (8-bit bytes), not
in characters.
RDB$FIELD_SCALE integer For numeric data types,
the scale factor to be
applied when interpreting
the contents of the field
represented by this row.
This scale factor must be
interpreted according to
the rules for interpreting
the DSC$B_SCALE field of
class SD descriptors (as
defined in the OpenVMS
Calling Standard). For
date-time data types,
RDB$FIELD_SCALE is
fractional seconds
precision. For other
non-numeric data types,
RDB$FIELD_SCALE is 0.
RDB$SYSTEM_FLAG integer A bit mask where the
following bits are set:
o If Bit 0 is clear,
this is a user-defined
domain.
o If Bit 0 is set, this is
a system domain.
RDB$VALIDATION_BLR list The BLR that represents the
of byte validation expression to be
varying checked each time a column
based on this domain is
updated.
RDB$COMPUTED_BLR list The BLR that represents
of byte the expression used to
varying calculate a value for
the column based on this
domain.
RDB$EDIT_STRING varchar(25The edit string used
by interactive SQL when
printing the column based
on this domain. RDB$EDIT_
STRING can be null.
RDB$MISSING_VALUE list The value used when the
of byte missing value of the column
varying based on this domain is
retrieved or displayed.
RDB$MISSING_VALUE does
not store any value in
a column; instead, it
flags the column value
as missing.
RDB$FIELD_SUB_TYPE integer A value that describes the
data subtype of RDB$FIELD_
TYPE as shown in the
RDB$FIELD_SUB_TYPE Help
topic.
RDB$DESCRIPTION list A user-supplied description
of byte of this domain.
varying
RDB$VALIDATION_SOURCE list The user's source text for
of byte the validation criteria.
varying
RDB$COMPUTED_SOURCE list The user's source used
of byte to calculate a value at
varying execution time.
RDB$QUERY_NAME char(31) The query name of this
domain. Column attributes
in RDB$RELATION_FIELDS take
precedence over attributes
in
RDB$FIELDS.
If the attribute value is
missing in
RDB$RELATION_FIELDS, the
value from RDB$FIELDS is
used.
RDB$QUERY_NAME can be null.
RDB$QUERY_HEADER list The query header of
of byte the domain is used by
varying interactive SQL. Column
attributes in
RDB$RELATION_FIELDS take
precedence over attributes
in RDB$FIELDS.
If the attribute value is
missing in
RDB$RELATION_FIELDS, the
value from RDB$FIELDS is
used.
RDB$DEFAULT_VALUE list The default value used by
of byte non-SQL interfaces when
varying no value is specified for
a column during a STORE
clause. It differs from
RDB$MISSING_VALUE in that
it holds an actual column
value.
Column attributes in
RDB$RELATION_FIELDS take
precedence over attributes
in RDB$FIELDS.
If the attribute value is
missing in
RDB$RELATION_FIELDS, the
value from RDB$FIELDS is
used.
RDB$SEGMENT_LENGTH integer The length of a segmented
string segment. For date-
time interval fields, the
interval leading field
precision.
RDB$EXTENSION_PARAMETERS list Reserved for future use.
of byte
varying
RDB$CDD_NAME list The fully qualified name of
of byte the dictionary entity upon
varying which the domain definition
is based, as specified
in the SQL clause, FROM
PATHNAME.
RDBVMS$COLLATION_NAME char(31) The name of the collating
sequence for the domain.
RDB$DEFAULT_VALUE2 list The BLR for the SQL default
of byte value. This value is used
varying when no value is provided
in an SQL INSERT statement.
RDB$SECURITY_CLASS char(20) Reserved for future use.
RDB$FLAGS integer Flags.
RDB$CREATED date vms Set when the domain is
created.
RDB$LAST_ALTERED date vms Set when SQL ALTER DOMAIN
statement used.
RDB$FIELD_CREATOR char(31) Creator of this domain.
1 – RDB$FLAGS
Represents flags for RDB$FIELDS system table.
Bit
Position Description
0 A SQL CHECK constraint is defined on this domain.
1 AUTOMATIC set on insert.
2 AUTOMATIC set on update.
3 If check constraint fails, use name in message.
4 Column is computed an IDENTITY sequence.
5 View column is based on a read-only, or dbkey column.