Question

In an Oracle database, we have created 22 materialized views and we have created a procedure to refresh all these MV’s. All 22 materialized views refresh successfully.

On the last day of every month, we wanted to refresh the materialized views and copy the data to historical tables. These historical tables have the same structure along with three additional columns that contain the date the data was copied along with the month and year that the data represents.

• copy_date will be the sysdate when the data is copied to history table
• month and year will be passed in to the stored procedure.

For example, if I forgot to refresh at the end of January and remembered on February 4

• copy_date: 4th of feb
• ‘month’ and ‘year’ are : FEB and 2012

The reporting team will use these columns to filter the data in order to analyze it.

example : Table A

study country state
abc    india    ap
bcd    china    xx

I need a procedure that copies the data to a history table like:

month year copy_date     study  country state
jan   2013 01-01-2013    abc    india   ap

When I run this procedure, I want to enter values for the month and year parameters (jan and 2013 in this case).

Answer 1

First, I’m not sure why you would bother passing in the month and year parameters rather than simply deriving that from the sysdate. In your example, you the month and year are based on the current sysdate whether you copy the data on January 30 or February 4.

One option would be

CREATE OR REPLACE PROCEDURE copy_a( p_month IN VARCHAR2, p_year IN NUMBER )
AS
BEGIN
  INSERT INTO a_history( month, year, copy_date, study, country, state )
    SELECT p_month, p_year, sysdate, study, country, state
      FROM a;
END;

You could also use dynamic SQL to avoid having to create 22 separate stored procedures. If the history tables always have the month, year, and copy_date as their first three columns and have the remaining columns in exactly the same order as the base table

CREATE OR REPLACE PROCEDURE copy_table( p_table_name IN VARCHAR2, 
                                        p_month IN VARCHAR2, 
                                        p_year IN NUMBER )
AS
  l_sql_stmt VARCHAR2(10000);
BEGIN
  l_sql_stmt := 'INSERT INTO ' || p_table_name || '_hist ' ||
                ' SELECT :mnth, :yr, sysdate, a.* ' ||
                '   FROM ' || p_table_name;
  EXECUTE IMMEDIATE l_sql_stmt 
    USING p_month, p_year;
END;