Anonymous Blocks

An anonymous block is one of the character blocks of a stored procedure and has no name. It is generally used for scripts or activities that are not executed frequently.

Syntax

Figure 1 shows the syntax diagram for an anonymous block.

Figure 1 anonymous_block::=

Details about the syntax diagram are as follows:

• The execution section of an anonymous block starts with a BEGIN statement, has a break with an END statement, and ends with a semicolon (;). Type a slash (/) and press Enter to execute the statement.

  NOTICE: The terminator “/” must be written in an independent row.

• The declaration section includes the variable definition, type, and cursor definition.

• A simplest anonymous block does not execute any commands. At least one statement, even a NULL statement, must be presented in any implementation blocks.

Parameter Description

• DECLARE

  Specifies an optional keyword used to begin a DECLARE statement. This keyword can be used to declare a data type, variable, or cursor. The use of this keyword depends on the context in which the block is located.

• declaration_statements

  Specifies the declaration of a data type, variable, cursor, exception, or procedure whose scope is limited to the block. Each declaration must be terminated with a semicolon (;).

• BEGIN

  Specifies the mandatory keyword for introducing an executable section. The section can contain one or more SQL or PL/SQL statements. A BEGIN-END block can contain nested BEGIN-END blocks.

• execution_statements

  Specifies PL/SQL or SQL statements. Each statement must be terminated with a semicolon (;).

• END

  Specifies the required keyword for ending a block.

Examples

-- Create a null statement block.
MogDB=# BEGIN
     NULL; 
END;
/

-- Create a demonstration table.
MogDB=# CREATE TABLE table1(id1 INT, id2 INT, id3 INT);
CREATE TABLE

-- Use an anonymous block to insert data.
MogDB=# BEGIN
             insert into table1 values(1,2,3);
            END;
            /
ANONYMOUS BLOCK EXECUTE

-- Query the inserted data.
MogDB=# select * from table1;
 id1 | id2 | id3
-----+-----+-----
   1 |   2 |   3
(1 rows)