PL/pgSQL – Row Type Variables

ByAdmin

In PostgreSQL’s PL/pgSQL language, you can use a row type variable to store and manipulate rows of data from database tables or other composite types. A row type variable is essentially a container that can hold an entire row of data, preserving the structure of the row, including the column names and data types.

Here’s how you declare and use a row type variable in PL/pgSQL:

DECLARE variable_name table_name%ROWTYPE;
  • variable_name is the name you want to give to the row type variable.
  • table_name is the name of the table or composite type whose structure you want to mimic in the row type variable.

Here’s an example that demonstrates the use of a row type variable. Consider a table named “employees” with columns “id,” “name,” and “salary.” You can create a row type variable to hold a row of data from this table:

DECLARE 
  emp_record employees%ROWTYPE; 
BEGIN 
  -- Assign a row from the "employees" table to the variable 
  SELECT * INTO emp_record FROM employees WHERE id = 1; 
  -- Access individual fields within the row variable 
  RAISE NOTICE 'Employee ID: %', emp_record.id; 
  RAISE NOTICE 'Employee Name: %', emp_record.name; 
  RAISE NOTICE 'Employee Salary: %', emp_record.salary; 
END;

In this example:

  • We declare a row type variable emp_record with the same structure as the “employees” table.
  • We use a SELECT statement with the INTO clause to retrieve a row from the “employees” table and assign it to the emp_record variable based on a condition (in this case, where id is 1).
  • We then access individual fields within the emp_record variable to retrieve and display specific data from the row.

Row type variables are particularly useful when you need to work with entire rows of data, such as when querying a table or returning rows from a function. They allow you to maintain the structure of the row, making it easier to interact with the data contained within it.

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