Author Archive

DB2 Optimizer Overview | How Db2 selects the optimum path

The DB2 optimizer is the main component of DB2. As its name implies, it analyzes the SQL statements and determines the most efficient path to access the desired data from the tables. When the SQl statement is fired, it access the statistics stored in the DB2 catalog to determine the best path to suffice the

Cobol-DB2 Cursor Overview

Db2-Cursor: Cursors in the application program are used to retrieve the multiple rows and process them one by one . Generally by using a singleton select statement in the application program, it is possible to retrieve only one row at a time as the host variable structure allows keeping one value at a time. Ex:

CICS Tutorial

CICS Tutorial part-1 CICS is a transaction procession system owned by IBM and runs under Z/OS operating system. CICS stands for Customer Information Control System which works as a front end for the business applications written in COBOL, PL/1, C, C++, Assembler, PHP and JAVA but most of the applications which CICS supports are written

COBOL Renames Clause with Examples

COBOL Renames clause is used to regroup the elementary data items and gives them an alternative name. This is a logical grouping of the elementary data items which are defined in a sequential order.It is useful for renaming by overlapping elementary elements.66 Level number is used for defining it. [crayon-5d2f1672d649b128917787/] – 01 , 77 levels

DB2 Table Space Types and its usage

Table Space concept in DB2: Table space is a database object where actually the table data gets stored. It is a like child of the database, where there can be multiple table spaces within a database. Each table space contains the ‘containers’. There can be one or more containers per table space. Containers can be

COBOL Arrays or Tables

Single dimensional arrays: Arrays are data structures that are used to simplify coding and improve processing efficiency. The primary uses of arrays are to define:  a series of similarly formatted input or output record fields in the FILE SECTION  a group of accumulators in WORKING-STORAGE for different categories of totals  a table in WORKING-STORAGE that

STRING AND UNSTRING IN COBOL

STRING AND UNSTRING with examples: TALLYING and COUNT options String is used to combine two or more strings/variables in to a single string. Examples: [crayon-5d2f1672d6c6a578512826/] If you display the ‘name-in’ it shows like ‘ Mahender Reddy G ‘ i.e: it shows the full length of each variable INCLUDING THE SPACES. So this can be avoided

ESCAPE clause in SQL DB2

ESCAPE in DB2 Mainframes: In SQL the percent sign(%) and the under score(_) has special meaning. %’ – represents any set of characters _ – under score represents any single character. [crayon-5d2f1672d72c7434402262/] This will display all the email ids starting with reddy like reddy123,reddy_34 etc. But here the requirement is to display the email ids

Debug Tool Commands – Mainframes

IBM Debug Tool Commands for mainframes a Quick reference F2           – Line by Line Execution F9           – break point to break point execution F10          – Debug in full screen mode Setting Break Point-> – Place the cursor on the line where the break point

CICS Scrolling logic with examples

CICS scrolling logic looks very simple in algorithm representation but implementing it practically so many questions arises. This topic is to clear all the queries related to CICS scrolling (page Up / Down) logic with suitable examples. Let me give few basic points before getting into detailed implementation logic. Decide the number of rows(MAX-SCRN-SIZE) to
Bitnami