DML Statements With Parameters

If DML statements (SELECT, INSERT, UPDATE, DELETE, etc.) in the body of a module (procedure, function, trigger or block) use parameters, only named parameters can be used.If DML statements contain named parameters, then they must be previously declared as local variables using DECLARE [VARIABLE] in the declaration section of the module, or as input or output variables in the module header.

When a DML statement with parameters is included in PSQL code, the parameter name must be prefixed by a colon (‘:’) in most situations.The colon is optional in statement syntax that is specific to PSQL, such as assignments and conditionals and the INTO clause.The colon prefix on parameters is not required when calling stored procedures from within another PSQL module.

Stored procedures and functions (including those defined in packages) are executed in the context of the transaction in which they are called.Triggers are executed as an intrinsic part of the operation of the DML statement: thus, their execution is within the same transaction context as the statement itself.Individual transactions are launched for database event triggers fired on connect or disconnect.

Statements that start and end transactions are not available in PSQL, but it is possible to run a statement or a block of statements in an autonomous transaction.