The TRIGGERS are the event driven database programs which are triggered automatically by the database. The TRIGGERS are created using the CREATE TRIGGER statement.For example, we want to create a TRIGGER which will update ORDER_COMMISION column of the ORDERS table to 5% of the ORDER_TOTAL value after every new record ... Read More

The TRIGGERS are database programs which are triggered automatically by DBMS in response to any modification done on the specified table. A TRIGGER can be associated with only a single table and they cannot be skipped if the desired event occurs.The TRIGGERS are like STORED PROCEDURES in the sense, both ... Read More

A STORED PROCEDURE generally contains the SQLs which are often used in one or more programs. The main advantage of STORED PROCEDURE is that it reduces the data traffic between the COBOL and DB2 as the STORED PROCEDURES resides in DB2.A COBOL-DB2 program can call a STORED PROCEDURE using a ... Read More

Problem: What will be the result if a COBOL-DB2 program tries to query a DB2 table, but the database in which table is residing is down?SolutionWhen we try to access any table using a COBOL-DB2 program and the DB2 database in which that table is residing is down then the ... Read More

We can find the duplicate TRANSACTION_ID in the ORDERS DB2 table using the below query:ExampleSELECT TRANSACTION_ID, COUNT(*) AS TRANSACTION_COUNT FROM ORDER GROUP BY TRANSACTION_ID HAVING COUNT(*) > 1The purpose of COUNT(*) is to count the number of rows. We will group the result based on the TRANSACTION_ID using GROUP BY ... Read More

Problem: Write a SQL query to count the number of orders which were placed today from the ORDERS DB2 table. (The date should not be hardcoded)SolutionWe can find the count of orders which are placed today using the below DB2 query:ExampleSELECT COUNT(ORDER_ID) AS ORDER_COUNT FROM ORDERS WHERE ORDER_DATE = CURRENT ... Read More

Problem: Write a SQL query to display 2 columns. First column should have ORDER_ID, the second column should give the value as YES/NO for free shipping based on ORDER_TOTAL > 500.SolutionThe query to display ORDER_ID and free shipping result based on the ORDER_TOTAL criteria can be written as below.ExampleSELECT ORDER_ID, ... Read More

Problem: A COBOL-DB2 program failed due to deadlock. How will you find the resource due to which the program failed?SolutionA DEADLOCK condition occurs when two or more applications are stuck, waiting for each other to release the locks on the resources needed by them. A detailed information and logs can ... Read More

A DB2 LOCK PROMOTION is defined as the process of acquiring more restrictive locks on a particular resource. DB2 uses LOCK PROMOTION for the concurrent processes which are trying to access the same DB2 resource. Basically, there are three types of locks.Shared lock(S)The concurrent processes can place a shared lock ... Read More

The direct index look-up is chosen by the DB2 optimizer when all the columns used in the predicate of the WHERE clause is part of the index.For example, if we have ORDERS DB2 table as below.ORDER_IDORDER_DATEORDER_TOTALZ2234530-10-2020342Z3341214-08-2020543Z5699019-10-2020431Z5690221-09-20206743Z9978104-11-2020443Z5611229-08-2020889In this table, there is one index which is built having columns named ORDER_ID and ... Read More