Firebird 2.1 Language Reference Update

Changed in: 2.0
Context variables
Description: CURRENT_TIMESTAMP returns the current server date and time. In versions prior to 2.0, the fractional
part used to be always “.0000”, giving an effective precision of 0 decimals. From Firebird 2.0 onward
you can specify a precision when polling this variable. The default is 3 decimals, i.e. milliseconds precision.
Type: TIMESTAMP
Syntax:
Examples:
Notes:
CURRENT_TIMESTAMP [(precision)]
precision ::= 0 | 1 | 2 | 3
The optional precision argument is not supported in ESQL.
select current_timestamp from rdb$database
-- returns e.g. 2008-08-13 14:20:19.6170
select current_timestamp(2) from rdb$database
-- returns e.g. 2008-08-13 14:20:23.1200
• The default precision of CURRENT_TIME is still 0 decimals, so in Firebird 2.0 and up CURRENT_TIMESTAMP
is no longer the exact sum of CURRENT_DATE and CURRENT_TIME, unless you explicitly specify a precision.
• Within a PSQL module (procedure, trigger or executable block), the value of CURRENT_TIMESTAMP will
remain constant every time it is read. If multiple modules call or trigger each other, the value will remain
constant throughout the duration of the outermost module. If you need a progressing value in PSQL (e.g. to
measure time intervals), use 'NOW'.
Available in: DSQL, PSQL
Added in: 1.5
CURRENT_TRANSACTION
Description: CURRENT_TRANSACTION contains the unique identifier of the current transaction.
Type: INTEGER
Examples:
select current_transaction from rdb$database
New.Txn_ID = current_transaction;
The value of CURRENT_TRANSACTION is stored on the database header page and reset to 0 upon restore. It is
incremented with every new transaction.
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