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CREATE PROCEDURE
Description
Creates a stored procedure.
Syntax
CREATE PROCEDURE procname [(<inparam> [, <inparam> ...])] [RETURNS (<outparam> [, <outparam> ...])] AS [<declarations>] BEGIN [<PSQL statements>] END <inparam> ::= <param_decl> [{= | DEFAULT} value] <outparam> ::= <param_decl> <param_decl> ::= paramname <type> [NOT NULL] [COLLATE collation] <type> ::= sql_datatype | [TYPE OF] domain <declarations> ::= See PSQL::DECLARE for the exact syntax /* If sql_datatype is a string type, it may include a character set */
TYPE OF COLUMN in parameter and variable declarations
Changed in: 2.5
Description
Analogous to the “TYPE OF domain” syntax supported since version 2.1, it is now also possible to declare variables and parameters as having the type of an existing table or view column. Only the type itself is used; in the case of string types, this includes the character set and the collation. Constraints and default values are never copied from the source column.
Example
/* Assuming DDL autocommit and connection charset UTF8 */ create domain dphrase as varchar(200) character set utf8 collate unicode_ci_ai; create table phrases (phrase dphrase); set term #; create procedure equalphrases (a type of column phrases.phrase,
b type of column phrases.phrase)
returns (res varchar(30)) as begin if (a = b) then res = 'Yes'; else res = 'No'; suspend; end# set term ;# select res from equalphrases('Appel', 'appèl');
- - result is 'Yes'
Warnings:
- For text types, character set and collation are included by TYPE OF COLUMN – just as when [TYPE OF] <domain> is used. However, due to a bug, the collation is not always taken into consideration when comparisons (e.g. equality tests) are made. In cases where the collation is of importance, test your code thoroughly before deploying! This bug is fixed for Firebird 3.
- If the column's type is changed at a later time, PSQL code using that column may become invalid. For information on how to detect this, please read the note The RDB$VALID_BLR field, near the end of this document.
Domains supported in parameter and variable declarations
Changed in: 2.1
Description
Firebird 2.1 and up allow the use of domains instead of SQL datatypes when declaring input/output parameters and local variables. With the TYPE OF modifier only the domain's type is used, not its NOT NULL setting, CHECK constraint and/or default value.
Example
create domain bool3 smallint check (value is null or value in (0,1)); create domain bigposnum bigint check (value >= 0);
/* Determines if A is a multiple of B: */ set term #; create procedure ismultiple (a bigposnum, b bigposnum) returns (res bool3) as declare ratio type of bigposnum; -- ratio is a bigint declare remainder type of bigposnum; -- so is remainder begin if (a is null or b is null) then res = null; else if (b = 0) then begin if (a = 0) then res = 1; else res = 0; end else begin ratio = a / b; -- integer division! remainder = a - b*ratio; if (remainder = 0) then res = 1; else res = 0; end end# set term ;#
Warning: If a domain's definition is changed, existing PSQL code using that domain may become invalid. For information on how to detect this, please read the note The RDB$VALID_BLR field?, near the end of this document.
COLLATE in variable and parameter declarations
Changed in: 2.1
Description
Firebird 2.1 and up allow COLLATE clauses in declarations of input/output parameters and local variables.
Example
create procedure SpanishToDutch (es_1 varchar(20) character set iso8859_1 collate es_es, es_2 my_char_domain collate es_es) returns (nl_1 varchar(20) character set iso8859_1 collate du_nl, nl_2 my_char_domain collate du_nl) as declare s_temp varchar(100) character set utf8 collate
unicode;
begin ... ... end
NOT NULL in variable and parameter declarations
Changed in: 2.1
Description
Firebird 2.1 and up allow NOT NULL constraints in declarations of input/output parameters and local variables.
Example
create procedure RegisterOrder(order_no int not null, description varchar(200) not null) returns (ticket_no int not null) as declare temp int not null; begin ... ... end
Default argument values
Changed in: 2.0
Description
It is now possible to provide default values for stored procedure arguments, allowing the caller to omit one or more items (possibly even all) from the end of the argument list.
Syntax
CREATE PROCEDURE procname (<inparam> [, <inparam> ...]) ... <inparam> ::= paramname datatype [{= | DEFAULT} value]
Important: If you provide a default value for a parameter, you must do the same for any and all parameters following it.
BEGIN ... END blocks may be empty
Changed in: 1.5
Description
BEGIN … END blocks may be empty in Firebird 1.5 and up, allowing you to write stub code without having to resort to dummy statements.
Example
create procedure grab_ints (a integer, b integer) as begin end