First two are almost similar, Last one from mainframegurukul covers most of the jcl These will guide us through the Cobol DB2 Application Programming. COBOL Tutorial for Beginners – Learn COBOL in simple and easy steps starting from basic to advanced concepts with examples including Overview. VSAM is used by COBOL and CICS in Mainframes to store and retrieve data. VSAM makes it easier for application programs to execute an input-output.
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This is very cumbersome. When there are multiple items of the same type, you can use arrays. A COBOL table or array is simply a data structure consisting of a collection of elements valuesall of which have the same data description, maibframegurukul as a table of monthly sales. Think of a table as a matrixa grid of elements.
Let’s establish an array of monthly sales amounts for the company. The array consists of 12 sales amounts.
You’d refer to any element by its position in the mainframeugrukul. For example, the sales in June i. The elements of a table could be elementary or group data items.
For example, you could create a table of employee SSN and their names.
Referring to an item in the table A table name is a collective name for all the elements in it. However, to identify the items of a table, you can use two techniques viz. Subscript is the absolute position of the element in the table. As an example, let’s assume that a bank’s customer accounts information is stored in a table. Every customer account has a cash account no.
The code snippet below shows this. Array elements are laid out in computer memory in adjacent locations. Because arrays are contiguous in memory, data processing is faster. At run-time, subscripts are converted to a displacement from the start of the table. An array of 10 items may be stored at displacements 0, 49, 98,Index is the displacement of an element from the start of the table. Indexes perform better than subscripts, as indexes already store the offset and does not have to be calculated at run-time.
The SET statement can be used to manipulate an index.
MAINFRAME TUTORIALS, COBOL DB2 JCL CICS Tutorials Interview Questions
Setting an index to 2, will cause the compiler to correctly calculate the byte offset and point to the 2 nd element in the table. Likewise, setting an index up by one will move the index to the next element, regardless of the size of the element.
Suppose, we are interested to find the average sales in the manufacturing organization example. Initialize the index I to 1. Such pre-calculated tables come in very handy. Lookup tables save processing time by searching for an input x and finding the output y from the table, rather than do an expensive computation.
Let us take an example. We must transform 01, 02, 03, I then construct an array out of this variable by slicing it into twelve parts. A central store for static data A well-designed program has the static data centralized at one place. Let’s establish an example to compute the tax of a US citizen. Tax in the United States is computed as follows. A generic sub-routine can be written to compute tax as follows. We’ll introduce you to the hardware and peripherals.
Support programs for OS/360 and successors
We’ll talk mainfraamegurukul the operating system, the software installed mainfrajegurukul a mainframe. We’ll also talk about the mainframmegurukul people who work on a mainframe. In a nutshell, we’ll de-mystify the mainframe. Readers based in Indiacan buy the e-book for Rs. International readers based in the US and other countries can click here to purchase the e-book. A table name is a collective name for all the elements in it. The compiler automatically calculates the value contained in the index as the occurrence number minus 1 multiplied by the size of the table element.
Table processing often involves traversing the table and accessing array elements. Tables can be pre-filled with information. A well-designed program has the static data centralized at one place. To many people who are thrown to work at a mainframe computer on their first job, they feel lost.
Mainframe people seem to speak a completely different language and that doesn’t make life easy. What’s more, the books and manuals are incredibly hard to comprehend.