Functions for Sequences (Generators)
RDB$GET_CONTEXT()
Retrieves the value of a context variable from a namespace
VARCHAR(255)
RDB$GET_CONTEXT ('<namespace>', <varname>) <namespace> ::= SYSTEM | USER_SESSION | USER_TRANSACTION | DDL_TRIGGER <varname> ::= A case-sensitive quoted string of max. 80 characters
Parameter | Description |
---|---|
namespace |
Namespace |
varname |
Variable name;case-sensitive with a maximum length of 80 characters |
The USER_SESSION
and USER_TRANSACTION
namespaces are initially empty.A user can create and set variables with RDB$SET_CONTEXT()
and retrieve them with RDB$GET_CONTEXT()
.The SYSTEM
namespace is read-only.The DDL_TRIGGER
namespace is only valid in DDL triggers, and is read-only.The SYSTEM
and DDL_TRIGGER
namespaces contain a number of predefined variables, shown below.
If the polled variable exists in the given namespace, its value will be returned as a string of max. 255 characters.If the namespace doesn’t exist or if you try to access a non-existing variable in the SYSTEM
or DDL_TRIGGER
namespace, an error is raised.If you request a non-existing variable in one of the user namespaces, NULL
is returned.Both namespace and variable names must be given as single-quoted, case-sensitive, non-NULL
strings.
SYSTEM
NamespaceCLIENT_ADDRESS
For TCP, this is the IP address.For XNET, the local process ID.For all other protocols this variable is NULL
.
CLIENT_HOST
The wire protocol host name of remote client.Value is returned for all supported protocols.
CLIENT_PID
Process ID of remote client application.
CLIENT_PROCESS
Process name of remote client application.
CURRENT_ROLE
Same as global [fblangref50-contextvars-current-role] variable.
CURRENT_USER
Same as global [fblangref50-contextvars-current-user] variable.
DB_FILE_ID
Unique filesystem-level ID of the current database.
DB_GUID
GUID of the current database.
DB_NAME
Canonical name of current database;either the full path to the database or — if connecting via the path is disallowed — its alias.
DECFLOAT_ROUND
Rounding mode of the current connection used in operations with DECFLOAT
values.See also SET DECFLOAT
.
DECFLOAT_TRAPS
Exceptional conditions for the current connection in operations with DECFLOAT
values that cause a trap.See also SET DECFLOAT
.
EFFECTIVE_USER
Effective user at the point RDB$GET_CONTEXT
is called;indicates privileges of which user is currently used to execute a function, procedure, trigger.
ENGINE_VERSION
The Firebird engine (server) version.
EXT_CONN_POOL_ACTIVE_COUNT
Count of active connections associated with the external connection pool.
EXT_CONN_POOL_IDLE_COUNT
Count of currently inactive connections available in the connection pool.
EXT_CONN_POOL_LIFETIME
External connection pool idle connection lifetime, in seconds.
EXT_CONN_POOL_SIZE
External connection pool size.
GLOBAL_CN
Most current value of global Commit Number counter.
ISOLATION_LEVEL
The isolation level of the current transaction: 'READ COMMITTED'
, 'SNAPSHOT'
or 'CONSISTENCY'
.
LOCK_TIMEOUT
Lock timeout of the current transaction.
NETWORK_PROTOCOL
The protocol used for the connection: 'TCPv4'
, 'TCPv6'
, 'XNET'
or NULL
.
PARALLEL_WORKERS
The maximum number of parallel workers of the connection.
READ_ONLY
Returns 'TRUE'
if current transaction is read-only and 'FALSE'
otherwise.
REPLICA_MODE
Replica mode of the database: 'READ-ONLY'
, 'READ-WRITE'
and NULL
.
REPLICATION_SEQUENCE
Current replication sequence (number of the latest segment written to the replication journal).
SESSION_ID
Same as global [fblangref50-contextvars-current-connection] variable.
SESSION_IDLE_TIMEOUT
Connection-level idle timeout, or 0
if no timeout was set.When 0
is reported the database ConnectionIdleTimeout
from databases.conf
or firebird.conf
applies.
SESSION_TIMEZONE
Current session time zone.
SNAPSHOT_NUMBER
Current snapshot number for the transaction executing this statement.For SNAPSHOT
and SNAPSHOT TABLE STABILITY
, this number is stable for the duration of the transaction;for READ COMMITTED
this number will change (increment) as concurrent transactions are committed.
STATEMENT_TIMEOUT
Connection-level statement timeout, or 0
if no timeout was set.When 0
is reported the database StatementTimeout
from databases.conf
or firebird.conf
applies.
TRANSACTION_ID
Same as global [fblangref50-contextvars-current-transaction] variable.
WIRE_COMPRESSED
Compression status of the current connection.If the connection is compressed, returns TRUE
;if it is not compressed, returns FALSE
.Returns NULL
if the connection is embedded.
WIRE_CRYPT_PLUGIN
If connection is encrypted - returns name of current plugin, otherwise NULL
.
WIRE_ENCRYPTED
Encryption status of the current connection.If the connection is encrypted, returns TRUE
;if it is not encrypted, returns FALSE
.Returns NULL
if the connection is embedded.
DDL_TRIGGER
NamespaceThe DDL_TRIGGER
namespace is valid only when a DDL trigger is running.Its use is also valid in stored procedures and functions when called by DDL triggers.
The DDL_TRIGGER
context works like a stack.Before a DDL trigger is fired, the values relative to the executed command are pushed onto this stack.After the trigger finishes, the values are popped.So in the case of cascade DDL statements, when a user DDL command fires a DDL trigger and this trigger executes another DDL command with EXECUTE STATEMENT
, the values of the DDL_TRIGGER
namespace are the ones relative to the command that fired the last DDL trigger on the call stack.
EVENT_TYPE
event type (CREATE
, ALTER
, DROP
)
OBJECT_TYPE
object type (TABLE
, VIEW
, etc)
DDL_EVENT
event name (<ddl event item>
), where <ddl event item>
is EVENT_TYPE || ' ' || OBJECT_TYPE
OBJECT_NAME
metadata object name
OLD_OBJECT_NAME
for tracking the renaming of a domain (see note)
NEW_OBJECT_NAME
for tracking the renaming of a domain (see note)
SQL_TEXT
sql statement text
Note
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