The Firebird 5.0 Language Reference

Reserved Words and KeywordsMonitoring Tables

When you create a database, the Firebird engine creates a lot of system tables.Metadata — the descriptions and attributes of all database objects — are stored in these system tables.

System table identifiers all begin with the prefix RDB$.

List of System Tables

[fblangref-appx04-authmapping]: Stores authentication and other security mappings
[fblangref-appx04-backuphistory]: History of backups performed using nBackup
[fblangref-appx04-charactersets]: Names and describes the character sets available in the database
[fblangref-appx04-chkconstraints]: Cross-references between the names of constraints (NOT NULL constraints, CHECK constraints and ON UPDATE and ON DELETE clauses in foreign key constraints) and their associated system-generated triggers
[fblangref-appx04-collations]: Collations for all character sets
[fblangref-appx04-config]: Virtual table with configuration settings applied for the current database
[fblangref-appx04-database]: Basic information about the database
[fblangref-appx04-dbcreators]: A list of users granted the CREATE DATABASE privilege when using the specified database as a security database
[fblangref-appx04-dependencies]: Information about dependencies between database objects
[fblangref-appx04-exceptions]: Custom database exceptions
[fblangref-appx04-fields]: Column and domain definitions, both system and custom
[fblangref-appx04-fielddims]: Dimensions of array columns
[fblangref-appx04-files]: Information about secondary files and shadow files
[fblangref-appx04-filters]: Information about BLOB filters
[fblangref-appx04-formats]: Information about changes in the formats of tables
[fblangref-appx04-functions]: Information about external functions
[fblangref-appx04-funcargs]: Attributes of the parameters of external functions
[fblangref-appx04-generators]: Information about generators (sequences)
[fblangref-appx04-idxsegments]: Segments and index positions
[fblangref-appx04-indices]: Definitions of all indexes in the database (system- or user-defined)
[fblangref-appx04-logfiles]: Not used in the current version
[fblangref-appx04-packages]: Stores the definition (header and body) of SQL packages
[fblangref-appx04-pages]: Information about database pages
[fblangref-appx04-procedures]: Definitions of stored procedures
[fblangref-appx04-procparams]: Parameters of stored procedures
[fblangref-appx04-refconstr]: Definitions of referential constraints (foreign keys)
[fblangref-appx04-relations]: Headers of tables and views
[fblangref-appx04-relconstr]: Definitions of all table-level constraints
[fblangref-appx04-relfields]: Top-level definitions of table columns
[fblangref-appx04-roles]: Role definitions
[fblangref-appx04-secclasses]: Access control lists
[fblangref-appx04-timezones]: Time zones
[fblangref-appx04-transacs]: State of multi-database transactions
[fblangref-appx04-triggers]: Trigger definitions
[fblangref-appx04-trigmsgs]: Trigger messages
[fblangref-appx04-types]: Definitions of enumerated data types
[fblangref-appx04-userprivs]: SQL privileges granted to system users
[fblangref-appx04-viewrelns]: Tables that are referred to in view definitions: one record for each table in a view

`RDB$AUTH_MAPPING`

RDB$AUTH_MAPPING stores authentication and other security mappings.

Column Name Data Type Description

Column Name	Data Type	Description
`RDB$MAP_NAME`	`CHAR(63)`	Name of the mapping
`RDB$MAP_USING`	`CHAR(1)`	Using definition: `P` - plugin (specific or any) `S` - any plugin serverwide `M` - mapping `*` - any method
`RDB$MAP_PLUGIN`	`CHAR(63)`	Mapping applies for authentication information from this specific plugin
`RDB$MAP_DB`	`CHAR(63)`	Mapping applies for authentication information from this specific database
`RDB$MAP_FROM_TYPE`	`CHAR(63)`	The type of authentication object (defined by plugin) to map from, or `*` for any type
`RDB$MAP_FROM`	`CHAR(255)`	The name of the authentication object to map from
`RDB$MAP_TO_TYPE`	`SMALLINT`	The type to map to `0` - `USER` `1` - `ROLE`
`RDB$MAP_TO`	`CHAR(63)`	The name to map to
`RDB$SYSTEM_FLAG`	`SMALLINT`	Flag: `0` - user-defined `1` or higher - system-defined
`RDB$DESCRIPTION`	`BLOB TEXT`	Optional description of the mapping (comment)

RDB$MAP_NAME

CHAR(63)

Name of the mapping

RDB$MAP_USING

CHAR(1)

Using definition:

P - plugin (specific or any)
S - any plugin serverwide
M - mapping
* - any method

RDB$MAP_PLUGIN

CHAR(63)

Mapping applies for authentication information from this specific plugin

RDB$MAP_DB

CHAR(63)

Mapping applies for authentication information from this specific database

RDB$MAP_FROM_TYPE

CHAR(63)

The type of authentication object (defined by plugin) to map from, or * for any type

RDB$MAP_FROM

CHAR(255)

The name of the authentication object to map from

RDB$MAP_TO_TYPE

SMALLINT

The type to map to

0 - USER
1 - ROLE

RDB$MAP_TO

CHAR(63)

The name to map to

RDB$SYSTEM_FLAG

SMALLINT

Flag:

0 - user-defined
1 or higher - system-defined

RDB$DESCRIPTION

BLOB TEXT

Optional description of the mapping (comment)

`RDB$EXCEPTIONS`

RDB$EXCEPTIONS stores custom database exceptions.

Column Name Data Type Description

Column Name	Data Type	Description
`RDB$EXCEPTION_NAME`	`CHAR(63)`	Custom exception name
`RDB$EXCEPTION_NUMBER`	`INTEGER`	The unique number of the exception assigned by the system
`RDB$MESSAGE`	`VARCHAR(1021)`	Exception message text
`RDB$DESCRIPTION`	`BLOB TEXT`	Could store text description of the exception
`RDB$SYSTEM_FLAG`	`SMALLINT`	Flag: `0` - user-defined `1` or higher - system-defined
`RDB$SECURITY_CLASS`	`CHAR(63)`	May reference a security class defined in the table `RDB$SECURITY_CLASSES`, to apply access control limits to all users of this exception
`RDB$OWNER_NAME`	`CHAR(63)`	The username of the user who created the exception originally

RDB$EXCEPTION_NAME

CHAR(63)

Custom exception name

RDB$EXCEPTION_NUMBER

INTEGER

The unique number of the exception assigned by the system

RDB$MESSAGE

VARCHAR(1021)

Exception message text

RDB$DESCRIPTION

BLOB TEXT

Could store text description of the exception

RDB$SYSTEM_FLAG

SMALLINT

Flag:

0 - user-defined
1 or higher - system-defined

RDB$SECURITY_CLASS

CHAR(63)

May reference a security class defined in the table RDB$SECURITY_CLASSES, to apply access control limits to all users of this exception

RDB$OWNER_NAME

CHAR(63)

The username of the user who created the exception originally

`RDB$FIELDS`

RDB$FIELDS stores definitions of columns and domains, both system and custom.This is where the detailed data attributes are stored for all columns.

Note	The column `RDB$FIELDS.RDB$FIELD_NAME` links to `RDB$RELATION_FIELDS.RDB$FIELD_SOURCE`, not to `RDB$RELATION_FIELDS.RDB$FIELD_NAME`.

Column Name Data Type Description

Column Name	Data Type	Description
`RDB$FIELD_NAME`	`CHAR(63)`	The unique name of the domain created by the user or of the domain automatically built for the table column by the system.System-created domain names start with the “RDB$” prefix
`RDB$QUERY_NAME`	`CHAR(63)`	Not used
`RDB$VALIDATION_BLR`	`BLOB BLR`	The binary language representation (BLR) of the expression of the `CHECK` constraint of a domain
`RDB$VALIDATION_SOURCE`	`BLOB TEXT`	The original source text in the SQL language specifying the check of the `CHECK` value
`RDB$COMPUTED_BLR`	`BLOB BLR`	The binary language representation (BLR) of the expression of a `COMPUTED BY` column, used to calculate the value of a computed column when it is accessed.
`RDB$COMPUTED_SOURCE`	`BLOB TEXT`	The original source text of the expression that defines a `COMPUTED BY` column
`RDB$DEFAULT_VALUE`	`BLOB BLR`	The binary language representation (BLR) of the default value for the field or domain
`RDB$DEFAULT_SOURCE`	`BLOB TEXT`	The default value in the source code, as an SQL constant or expression
`RDB$FIELD_LENGTH`	`SMALLINT`	Column size in bytes.`BOOLEAN` occupies 1 byte.`FLOAT`, `DATE`, `TIME`, `INTEGER` occupy 4 bytes.`DOUBLE PRECISION`, `BIGINT`, `TIMESTAMP`, `TIME WITH TIME ZONE`, `DECFLOAT(16)` and `BLOB` identifiers occupy 8 bytes.`TIMESTAMP WITH TIME ZONE` occupies 12 bytes.`INT128` and `DECFLOAT(34)` occupy 16 bytes.For the `CHAR` and `VARCHAR` data types, the column stores the maximum number of bytes specified when a string domain (column) is defined
`RDB$FIELD_SCALE`	`SMALLINT`	The negative number that specifies the scale for `DECIMAL` and `NUMERIC` columns — the number of digits after the decimal point
`RDB$FIELD_TYPE`	`SMALLINT`	Data type code for the column: `7` - `SMALLINT` `8` - `INTEGER` `10` - `FLOAT` `12` - `DATE` `13` - `TIME` `14` - `CHAR` `16` - `BIGINT` `23` - `BOOLEAN` `24` - `DECFLOAT(16)` `25` - `DECFLOAT(34)` `26` - `INT128` `27` - `DOUBLE PRECISION` `28` - `TIME WITH TIME ZONE` `29` - `TIMESTAMP WITH TIME ZONE35` - `TIMESTAMP` `37` - `VARCHAR` `261` - `BLOB` Codes for `DECIMAL` and `NUMERIC` are the same as for the integer types used for storage.
`RDB$FIELD_SUB_TYPE`	`SMALLINT`	Specifies the subtype for the BLOB data type: `0` - untyped (binary) `1` - text `2` - BLR `3` - access control list `4` - reserved for future use `5` - encoded table metadata description `6` - for storing the details of a cross-database transaction that ends abnormally `7` - external file description `8` - debug information (for PSQL) `< 0` - user-defined Specifies for the CHAR data type: `0` - untyped data `1` - fixed binary data Specifies the particular data type for the integer data types (`SMALLINT`, `INTEGER`, `BIGINT`, `INT128`) and for fixed-point numbers (`NUMERIC`, `DECIMAL`): `0` or `NULL` - the data type matches the value in the `RDB$FIELD_TYPE` field `1` - `NUMERIC` `2` - `DECIMAL`
`RDB$MISSING_VALUE`	`BLOB BLR`	Not used
`RDB$MISSING_SOURCE`	`BLOB TEXT`	Not used
`RDB$DESCRIPTION`	`BLOB TEXT`	Any domain (table column) comment text
`RDB$SYSTEM_FLAG`	`SMALLINT`	Flag: the value of 1 means the domain is automatically created by the system, the value of 0 means that the domain is defined by the user
`RDB$QUERY_HEADER`	`BLOB TEXT`	Not used
`RDB$SEGMENT_LENGTH`	`SMALLINT`	Specifies the length of the `BLOB` buffer in bytes for `BLOB` columns.Stores `NULL` for all other data types
`RDB$EDIT_STRING`	`VARCHAR(127)`	Not used
`RDB$EXTERNAL_LENGTH`	`SMALLINT`	The length of the column in bytes if it belongs to an external table.Always `NULL` for regular tables
`RDB$EXTERNAL_SCALE`	`SMALLINT`	The scale factor of an integer-type field in an external table;represents the power of 10 by which the integer is multiplied
`RDB$EXTERNAL_TYPE`	`SMALLINT`	The data type of the field as it is represented in an external table: `7` - `SMALLINT` `8` - `INTEGER` `10` - `FLOAT` `12` - `DATE` `13` - `TIME` `14` - `CHAR` `16` - `BIGINT` `23` - `BOOLEAN` `24` - `DECFLOAT(16)` `25` - `DECFLOAT(34)` `26` - `INT128` `27` - `DOUBLE PRECISION` `28` - `TIME WITH TIME ZONE` `29` - `TIMESTAMP WITH TIME ZONE35` - `TIMESTAMP` `37` - `VARCHAR` `261` - `BLOB`
`RDB$DIMENSIONS`	`SMALLINT`	Defines the number of dimensions in an array if the column is defined as an array.Always `NULL` for columns that are not arrays
`RDB$NULL_FLAG`	`SMALLINT`	Specifies whether the column can take an empty value (the field will contain `NULL`) or not (the field will contain the value of 1)
`RDB$CHARACTER_LENGTH`	`SMALLINT`	The length of `CHAR` or `VARCHAR` columns in characters (not in bytes)
`RDB$COLLATION_ID`	`SMALLINT`	The identifier of the collation for a character column or domain.If it is not defined, the value of the field will be 0
`RDB$CHARACTER_SET_ID`	`SMALLINT`	The identifier of the character set for a character column, `BLOB TEXT` column or domain
`RDB$FIELD_PRECISION`	`SMALLINT`	Specifies the total number of digits for the fixed-point numeric data type (`DECIMAL` and `NUMERIC`).The value is 0 for the integer data types, `NULL` is for other data types
`RDB$SECURITY_CLASS`	`CHAR(63)`	May reference a security class defined in the table `RDB$SECURITY_CLASSES`, to apply access control limits to all users of this domain
`RDB$OWNER_NAME`	`CHAR(63)`	The username of the user who created the domain originally

RDB$FIELD_NAME

CHAR(63)

The unique name of the domain created by the user or of the domain automatically built for the table column by the system.System-created domain names start with the “RDB$” prefix

RDB$QUERY_NAME

CHAR(63)

Not used

RDB$VALIDATION_BLR

BLOB BLR

The binary language representation (BLR) of the expression of the CHECK constraint of a domain

RDB$VALIDATION_SOURCE

BLOB TEXT

The original source text in the SQL language specifying the check of the CHECK value

RDB$COMPUTED_BLR

BLOB BLR

The binary language representation (BLR) of the expression of a COMPUTED BY column, used to calculate the value of a computed column when it is accessed.

RDB$COMPUTED_SOURCE

BLOB TEXT

The original source text of the expression that defines a COMPUTED BY column

RDB$DEFAULT_VALUE

BLOB BLR

The binary language representation (BLR) of the default value for the field or domain

RDB$DEFAULT_SOURCE

BLOB TEXT

The default value in the source code, as an SQL constant or expression

RDB$FIELD_LENGTH

SMALLINT

Column size in bytes.BOOLEAN occupies 1 byte.FLOAT, DATE, TIME, INTEGER occupy 4 bytes.DOUBLE PRECISION, BIGINT, TIMESTAMP, TIME WITH TIME ZONE, DECFLOAT(16) and BLOB identifiers occupy 8 bytes.TIMESTAMP WITH TIME ZONE occupies 12 bytes.INT128 and DECFLOAT(34) occupy 16 bytes.For the CHAR and VARCHAR data types, the column stores the maximum number of bytes specified when a string domain (column) is defined

RDB$FIELD_SCALE

SMALLINT

The negative number that specifies the scale for DECIMAL and NUMERIC columns — the number of digits after the decimal point

RDB$FIELD_TYPE

SMALLINT

Data type code for the column:

7 - SMALLINT
8 - INTEGER
10 - FLOAT
12 - DATE
13 - TIME
14 - CHAR
16 - BIGINT
23 - BOOLEAN
24 - DECFLOAT(16)
25 - DECFLOAT(34)
26 - INT128
27 - DOUBLE PRECISION
28 - TIME WITH TIME ZONE
29 - TIMESTAMP WITH TIME ZONE35 - TIMESTAMP
37 - VARCHAR
261 - BLOB

Codes for DECIMAL and NUMERIC are the same as for the integer types used for storage.

RDB$FIELD_SUB_TYPE

SMALLINT

Specifies the subtype for the BLOB data type:

0 - untyped (binary)
1 - text
2 - BLR
3 - access control list
4 - reserved for future use
5 - encoded table metadata description
6 - for storing the details of a cross-database transaction that ends abnormally
7 - external file description
8 - debug information (for PSQL)
< 0 - user-defined

Specifies for the CHAR data type:

0 - untyped data
1 - fixed binary data

Specifies the particular data type for the integer data types (SMALLINT, INTEGER, BIGINT, INT128) and for fixed-point numbers (NUMERIC, DECIMAL):

0 or NULL - the data type matches the value in the RDB$FIELD_TYPE field
1 - NUMERIC
2 - DECIMAL

RDB$MISSING_VALUE

BLOB BLR

Not used

RDB$MISSING_SOURCE

BLOB TEXT

Not used

RDB$DESCRIPTION

BLOB TEXT

Any domain (table column) comment text

RDB$SYSTEM_FLAG

SMALLINT

Flag: the value of 1 means the domain is automatically created by the system, the value of 0 means that the domain is defined by the user

RDB$QUERY_HEADER

BLOB TEXT

Not used

RDB$SEGMENT_LENGTH

SMALLINT

Specifies the length of the BLOB buffer in bytes for BLOB columns.Stores NULL for all other data types

RDB$EDIT_STRING

VARCHAR(127)

Not used

RDB$EXTERNAL_LENGTH

SMALLINT

The length of the column in bytes if it belongs to an external table.Always NULL for regular tables

RDB$EXTERNAL_SCALE

SMALLINT

The scale factor of an integer-type field in an external table;represents the power of 10 by which the integer is multiplied

RDB$EXTERNAL_TYPE

SMALLINT

The data type of the field as it is represented in an external table:

RDB$DIMENSIONS

SMALLINT

Defines the number of dimensions in an array if the column is defined as an array.Always NULL for columns that are not arrays

RDB$NULL_FLAG

SMALLINT

Specifies whether the column can take an empty value (the field will contain NULL) or not (the field will contain the value of 1)

RDB$CHARACTER_LENGTH

SMALLINT

The length of CHAR or VARCHAR columns in characters (not in bytes)

RDB$COLLATION_ID

SMALLINT

The identifier of the collation for a character column or domain.If it is not defined, the value of the field will be 0

RDB$CHARACTER_SET_ID

SMALLINT

The identifier of the character set for a character column, BLOB TEXT column or domain

RDB$FIELD_PRECISION

SMALLINT

Specifies the total number of digits for the fixed-point numeric data type (DECIMAL and NUMERIC).The value is 0 for the integer data types, NULL is for other data types

RDB$SECURITY_CLASS

CHAR(63)

May reference a security class defined in the table RDB$SECURITY_CLASSES, to apply access control limits to all users of this domain

RDB$OWNER_NAME

CHAR(63)

The username of the user who created the domain originally