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 Procedural SQL (PSQL) StatementsAggregate Functions 

The SYSTEM Namespace

Context variables in the SYSTEM namespace
CLIENT_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.

The DDL_TRIGGER Namespace

The 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.

Context variables in the DDL_TRIGGER namespace
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

ALTER DOMAIN old-name TO new-name sets OLD_OBJECT_NAME and NEW_OBJECT_NAME in both BEFORE and AFTER triggers.For this command, OBJECT_NAME will have the old object name in BEFORE triggers, and the new object name in AFTER triggers.