The Firebird 5.0 Language Reference

System PackagesTransaction Control

`OLD`

Record with the initial values of a row before update or delete

Available in

PSQL — triggers only,
DSQL — RETURNING clause of UPDATE, UPDATE OR INSERT and MERGE

Type

Record type

Syntax

OLD.column_name

Table 1. `OLD` Parameters
Parameter	Description
column_name	Column name to access

OLD contains the existing version of a database record just before a deletion or update.The OLD record is read-only.

Note	In multi-action triggers `OLD` is always available.However, if the trigger is fired by an `INSERT`, there is obviously no pre-existing version of the record.In that situation, reading from `OLD` will always return `NULL`.

`RESETTING`

Indicates if the trigger fired during a session reset

Available in

PSQL — triggers only

Type

BOOLEAN

Syntax

RESETTING

Its value is TRUE if session reset is in progress and FALSE otherwise.Intended for use in ON DISCONNECT and ON CONNECT database triggers to detect an ALTER SESSION RESET.

`ROW_COUNT`

Number of affected rows of the last executed statement

Available in

PSQL

Type

INTEGER

Syntax

ROW_COUNT

The ROW_COUNT context variable contains the number of rows affected by the most recent DML statement (INSERT, UPDATE, DELETE, SELECT or FETCH) in the current PSQL module.

Behaviour with SELECT and FETCH

After a singleton SELECT, ROW_COUNT is 1 if a data row was retrieved and 0 otherwise.
In a FOR SELECT loop, ROW_COUNT is incremented with every iteration (starting at 0 before the first).
After a FETCH from a cursor, ROW_COUNT is 1 if a data row was retrieved and 0 otherwise.Fetching more records from the same cursor does not increment ROW_COUNT beyond 1.

Note	`ROW_COUNT` cannot be used to determine the number of rows affected by an `EXECUTE STATEMENT` or `EXECUTE PROCEDURE` command.

Example

update Figures set Number = 0 where id = :id;
if (row_count = 0) then
  insert into Figures (id, Number) values (:id, 0);

`SQLCODE`

SQLCODE of the Firebird error in a WHEN … DO block

Available in

PSQL

Deprecated in

2.5.1

Type

INTEGER

Syntax

SQLCODE

In a “WHEN … DO” error handling block, the SQLCODE context variable contains the numeric value of the current SQL error code.SQLCODE is non-zero in WHEN … DO blocks, if the current error has a SQL error code.Outside error handlers, SQLCODE is always 0.Outside PSQL, it doesn’t exist at all.

Warning

SQLCODE is now deprecated in favour of the SQL-2003-compliant [fblangref50-contextvars-sqlstate] status code.Support for SQLCODE and WHEN SQLCODE will be discontinued in a future version of Firebird.

Example

when any
do
begin
  if (sqlcode <> 0) then
    Msg = 'An SQL error occurred!';
  else
    Msg = 'Something bad happened!';
  exception ex_custom Msg;
end

`SQLSTATE`

SQLSTATE code of the Firebird error in a WHEN … DO block

Available in

PSQL

Type

CHAR(5)

Syntax

SQLSTATE

In a “WHEN … DO” error handler, the SQLSTATE context variable contains the 5-character, SQL-compliant status code of the current error.Outside error handlers, SQLSTATE is always '00000'.Outside PSQL, it is not available at all.

Note

SQLSTATE is destined to replace SQLCODE.The latter is now deprecated in Firebird and will disappear in a future version.
Each SQLSTATE code is the concatenation of a 2-character class and a 3-character subclass.Classes 00 (successful completion), 01 (warning) and 02 (no data) represent completion conditions.Every status code outside these classes is an exception.Because classes 00, 01 and 02 don’t raise an error, they won’t ever show up in the SQLSTATE variable.
For a complete listing of SQLSTATE codes, consult the SQLSTATE Codes and Message Texts section in [fblangref50-appx02-errorcodes].

Example

when any
do
begin
  Msg = case sqlstate
          when '22003' then 'Numeric value out of range.'
          when '22012' then 'Division by zero.'
          when '23000' then 'Integrity constraint violation.'
          else 'Something bad happened! SQLSTATE = ' || sqlstate
        end;
  exception ex_custom Msg;
end

`CURRENT_DATE`

Current server date in the session time zone

Type

DATE

Syntax

CURRENT_DATE

Note

Within a PSQL module (procedure, trigger or executable block), the value of CURRENT_DATE 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 [fblangref50-contextvars-today].

Examples

select current_date from rdb$database
-- returns e.g. 2011-10-03

`'TODAY'`

Current date in cast context

Type

CHAR(5), or depends on explicit CAST

'TODAY' is not a variable, but a string literal or date mnemonic.It is, however, special in the sense that when you CAST() it to a date/time type, you will get the current date.If the target datetime type has a time component, it will be set to zero.'TODAY' is case-insensitive, and the engine ignores leading or trailing spaces when casting.

Note

'TODAY' always returns the actual date, even in PSQL modules, where [fblangref50-contextvars-current-date], [fblangref50-contextvars-current-time] and [fblangref50-contextvars-current-timestamp] return the same value throughout the duration of the outermost routine.This makes 'TODAY' useful for measuring time intervals in triggers, procedures and executable blocks (at least if your procedures are running for days).
Except in the situation mentioned above, reading CURRENT_DATE, is generally preferable to casting 'TODAY'.
Firebird 3.0 and earlier allowed the use of 'TODAY' in datetime literals (a.k.a. "`shorthand casts"`), this is no longer allowed since Firebird 4.0.
When cast to a TIMESTAMP WITH TIME ZONE, the time reflected will be 00:00:00 in UTC rebased to the session time zone.

Examples

select 'Today' from rdb$database
-- returns 'Today'

select cast('Today' as date) from rdb$database
-- returns e.g. 2011-10-03

select cast('TODAY' as timestamp) from rdb$database
-- returns e.g. 2011-10-03 00:00:00.0000

`'TOMORROW'`

Tomorrow’s date in cast context

Type

CHAR(8), or depends on explicit CAST

'TOMORROW' is not a variable, but a string literal.It is, however, special in the sense that when you CAST() it to a date/time type, you will get the date of the next day.See also [fblangref50-contextvars-today].

Examples

select 'Tomorrow' from rdb$database
-- returns 'Tomorrow'

select cast('Tomorrow' as date) from rdb$database
-- returns e.g. 2011-10-04

select cast('TOMORROW' as timestamp) from rdb$database
-- returns e.g. 2011-10-04 00:00:00.0000

`UPDATING`

Indicates if the trigger fired for an UPDATE operation

Available in

PSQL — triggers only

Type

BOOLEAN

Syntax

UPDATING

Intended for use in multi-action triggers.

Example

if (inserting or updating) then
begin
  if (new.serial_num is null) then
    new.serial_num = gen_id(gen_serials, 1);
end

`'YESTERDAY'`

Yesterday’s date in cast context

Type

CHAR(9), or depends on explicit CAST

'YESTERDAY' is not a variable, but a string literal.It is, however, special in the sense that when you CAST() it to a date/time type, you will get the date of the day before.See also [fblangref50-contextvars-today].

Examples

select 'Yesterday' from rdb$database
-- returns 'Yesterday'

select cast('Yesterday as date) from rdb$database
-- returns e.g. 2011-10-02

select cast('YESTERDAY' as timestamp) from rdb$database
-- returns e.g. 2011-10-02 00:00:00.0000

`USER`

Name of the user of the current connection

Type

VARCHAR(63)

Syntax

USER

USER is equivalent to (or, alias of) [fblangref50-contextvars-current-user].

Example

create trigger bi_customers for customers before insert as
begin
  New.added_by  = USER;
  New.purchases = 0;
end

`CURRENT_ROLE`

Current explicit role of the connection

Type

VARCHAR(63)

Syntax

CURRENT_ROLE

CURRENT_ROLE is a context variable containing the explicitly specified role of the currently connected user.If there is no explicitly specified role, CURRENT_ROLE is 'NONE'.

CURRENT_ROLE always represents a valid role or 'NONE'.If a user connects with a non-existing role, the engine silently resets it to 'NONE' without returning an error.

Note	Roles that are active by default and not explicitly specified on connect or using `SET ROLE` are not returned by `CURRENT_ROLE`.Use `RDB$ROLE_IN_USE` to check for all active roles.

Example

if (current_role <> 'MANAGER')
  then exception only_managers_may_delete;
else
  delete from Customers where custno = :custno;

`CURRENT_TIME`

Current server time in the session time zone, with time zone information

Type

TIME WITH TIME ZONE

Caution

Data type changed in Firebird 4.0 from TIME WITHOUT TIME ZONE to TIME WITH TIME ZONE.Use [fblangref50-contextvars-localtime] to obtain TIME WITHOUT TIME ZONE.

Syntax

CURRENT_TIME [ (<precision>) ]

<precision> ::= 0 | 1 | 2 | 3

The optional precision argument is not supported in ESQL.

Table 1. `CURRENT_TIME` Parameter
Parameter	Description
precision	Precision.The default value is 0.Not supported in ESQL

The default is 0 decimals, i.e. seconds precision.

Note

CURRENT_TIME has a default precision of 0 decimals, where CURRENT_TIMESTAMP has a default precision of 3 decimals.As a result, CURRENT_TIMESTAMP is not the exact sum of CURRENT_DATE and CURRENT_TIME, unless you explicitly specify a precision (i.e. CURRENT_TIME(3) or CURRENT_TIMESTAMP(0)).
Within a PSQL module (procedure, trigger or executable block), the value of CURRENT_TIME 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 [fblangref50-contextvars-now].

Warning

CURRENT_TIME and Firebird Time Zone Support

Firebird 4.0 added support for time zones.As part of this support, an incompatibility with the CURRENT_TIME expression was introduced compared to previous version.

Since Firebird 4.0, CURRENT_TIME returns the TIME WITH TIME ZONE type.In order for your queries to be compatible with database code of Firebird 4.0 and higher, Firebird 3.0.4 and Firebird 2.5.9 introduced the [fblangref50-contextvars-localtime] expression.In Firebird 3.0.4 and Firebird 2.5.9, LOCALTIME is a synonym for CURRENT_TIME.

In Firebird 5.0, LOCALTIME returns TIME [WITHOUT TIME ZONE]), while CURRENT_TIME returns TIME WITH TIME ZONE.

Examples

select current_time from rdb$database
-- returns e.g. 14:20:19.0000

select current_time(2) from rdb$database
-- returns e.g. 14:20:23.1200

`CURRENT_TIMESTAMP`

Current server date and time in the session time zone, with time zone information

Type

TIMESTAMP WITH TIME ZONE

Caution

Data type changed in Firebird 4.0 from TIMESTAMP WITHOUT TIME ZONE to TIMESTAMP WITH TIME ZONE.Use [fblangref50-contextvars-localtimestamp] to obtain TIMESTAMP WITHOUT TIME ZONE.

Syntax

CURRENT_TIMESTAMP [ (<precision>) ]

<precision> ::= 0 | 1 | 2 | 3

The optional precision argument is not supported in ESQL.

Table 1. `CURRENT_TIMESTAMP` Parameter
Parameter	Description
precision	Precision.The default value is 3.Not supported in ESQL

The default is 3 decimals, i.e. milliseconds precision.

Note

The default precision of CURRENT_TIME is 0 decimals, so CURRENT_TIMESTAMP is not the exact sum of CURRENT_DATE and CURRENT_TIME, unless you explicitly specify a precision (i.e. CURRENT_TIME(3) or CURRENT_TIMESTAMP(0)).
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 [fblangref50-contextvars-now].

Warning

CURRENT_TIMESTAMP and Firebird Time Zone Support

Firebird 4.0 added support for time zones.As part of this support, an incompatibility with the CURRENT_TIMESTAMP expression was introduced compared to previous versions.

Since Firebird 4.0, CURRENT_TIMESTAMP returns the TIMESTAMP WITH TIME ZONE type.In order for your queries to be compatible with database code of Firebird 4.0 and higher, Firebird 3.0.4 and Firebird 2.5.9 introduced the [fblangref50-contextvars-localtimestamp] expression.In Firebird 3.0.4 and Firebird 2.5.9, LOCALTIMESTAMP is a synonym for CURRENT_TIMESTAMP.

In Firebird 5.0, LOCALTIMESTAMP returns TIMESTAMP [WITHOUT TIME ZONE], while CURRENT_TIMESTAMP returns TIMESTAMP WITH TIME ZONE.

Examples

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

`CURRENT_TRANSACTION`

Unique identifier of the current transaction

Type

BIGINT

Syntax

CURRENT_TRANSACTION

The transaction identifier is derived from a counter on the database header page, which is incremented for each new transaction.When a database is restored, this counter is reset to zero.

Examples

select current_transaction from rdb$database

New.Txn_ID = current_transaction;

`CURRENT_USER`

Name of the user of the current connection

Type

VARCHAR(63)

Syntax

CURRENT_USER

CURRENT_USER is equivalent to [fblangref50-contextvars-user].

Example

create trigger bi_customers for customers before insert as
begin
    New.added_by  = CURRENT_USER;
    New.purchases = 0;
end

`DELETING`

Indicates if the trigger fired for a DELETE operation

Available in

PSQL — DML triggers only

Type

BOOLEAN

Syntax

DELETING

Intended for use in multi-action triggers.

Example

if (deleting) then
begin
  insert into Removed_Cars (id, make, model, removed)
    values (old.id, old.make, old.model, current_timestamp);
end

`GDSCODE`

Firebird error code of the error in a WHEN … DO block

Available in

PSQL

Type

INTEGER

Syntax

GDSCODE

In a “WHEN … DO” error handling block, the GDSCODE context variable contains the numeric value of the current Firebird error code.GDSCODE is non-zero in WHEN … DO blocks, if the current error has a Firebird error code.Outside error handlers, GDSCODE is always 0.Outside PSQL, it doesn’t exist at all.

Note	After `WHEN GDSCODE`, you must use symbolic names like `grant_obj_notfound` etc.But the `GDSCODE` context variable is an `INTEGER`.If you want to compare it against a specific error, the numeric value must be used, e.g.`335544551` for `grant_obj_notfound`.

Example

when gdscode grant_obj_notfound, gdscode grant_fld_notfound,
   gdscode grant_nopriv, gdscode grant_nopriv_on_base
do
begin
  execute procedure log_grant_error(gdscode);
  exit;
end