record

Updated on 2024-12-18 GMT+08:00

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record Variables

Perform the following operations to create a record variable:

Define a record type and use this type to declare a variable.

Syntax

For the syntax of the record type, see Figure 1.

Figure 1 Syntax of the record type

The syntax is described as follows:

record_type: record name
field: record columns
datatype: record data type
expression: expression for setting a default value

NOTE:

In GaussDB(DWS):

When assigning values to record variables, you can:
- Declare a record type and define member variables of this type when you declare a function or stored procedure.
- Assign the value of a record variable to another record variable.
- Use SELECT INTO or FETCH to assign values to a record type.
- Assign the NULL value to a record variable.
The INSERT and UPDATE statements cannot use a record variable to insert or update data.
Just like a variable, a record column of the compound type does not have a default value in the declaration.

Examples

    
     
       
       The table used in the following stored procedure is defined as follows:
CREATE TABLE emp_rec
(
    empno            numeric(4,0),
    ename            character varying(10),
    job              character varying(9),
    mgr              numeric(4,0),
    hiredate         timestamp(0) without time zone,
    sal              numeric(7,2),           
    comm             numeric(7,2),          
    deptno           numeric(2,0)
)
with (orientation = column,compression=middle)
distribute by hash (sal);
\d emp_rec
                Table "public.emp_rec"
  Column  |              Type              | Modifiers 
----------+--------------------------------+-----------
 empno    | numeric(4,0)                   | not null
 ename    | character varying(10)          | 
 job      | character varying(9)           | 
 mgr      | numeric(4,0)                   | 
 hiredate | timestamp(0) without time zone | 
 sal      | numeric(7,2)                   | 
 comm     | numeric(7,2)                   | 
 deptno   | numeric(2,0)                   | 

-- Perform array operations in the stored procedure.
CREATE OR REPLACE FUNCTION regress_record(p_w VARCHAR2)
RETURNS
VARCHAR2  AS $$
DECLARE

   -- Declare a record type.
   type rec_type is record (name  varchar2(100), epno int);
   employer rec_type;

   -- Use %type to declare the record type.
   type rec_type1 is record (name  emp_rec.ename%type, epno int not null :=10);
   employer1 rec_type1;

   -- Declare a record type with a default value.
   type rec_type2 is record (
         name varchar2 not null := 'SCOTT', 
         epno int not null :=10);
    employer2 rec_type2;
    CURSOR C1 IS  select ename,empno from emp_rec order by 1 limit 1;
            
BEGIN
      -- Assign a value to a member record variable.
     employer.name := 'WARD';
     employer.epno = 18;
     raise info 'employer name: % , epno:%', employer.name, employer.epno;

      -- Assign the value of a record variable to another variable.
     employer1 := employer;
     raise info 'employer1 name: % , epno: %',employer1.name, employer1.epno;
         
      -- Assign the NULL value to a record variable.
     employer1 := NULL;
     raise info 'employer1 name: % , epno: %',employer1.name, employer1.epno;

      -- Obtain the default value of a record variable.
     raise info 'employer2 name: % ,epno: %', employer2.name, employer2.epno;
            
      -- Use a record variable in the FOR loop.
      for employer in select ename,empno from emp_rec order by 1  limit 1 
          loop 
               raise info 'employer name: % , epno: %', employer.name, employer.epno;
          end loop;
         
      -- Use a record variable in the SELECT INTO statement.
      select ename,empno  into employer2 from emp_rec order by 1 limit 1;
      raise info 'employer name: % , epno: %', employer2.name, employer2.epno;
            
      -- Use a record variable in a cursor.
      OPEN C1;
      FETCH C1 INTO employer2;
      raise info 'employer name: % , epno: %', employer2.name, employer2.epno;
      CLOSE C1;        
      RETURN employer.name;
END;
$$
LANGUAGE plpgsql;

-- Invoke the stored procedure.
CALL regress_record('abc');
INFO:  employer name: WARD , epno:18
INFO:  employer1 name: WARD , epno: 18
INFO:  employer1 name: <NULL> , epno: <NULL>
INFO:  employer2 name: SCOTT ,epno: 10
-- Delete the stored procedure.
DROP PROCEDURE regress_record;

      

    
   