Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Problem: What is the purpose of the "FOR UPDATE OF" clause in a cursor? What will happen if we fire an UPDATE statement without using this clause in a COBOL-DB2 program?SolutionThe “FOR UPDATE OF” clause is given in the cursor declaration and it is used when we want to update the table. All the columns which need to be updated should be given in the cursor declaration.The “FOR UPDATE OF” clause will place the exclusive lock on all the qualifying rows once the cursor is open. We can also update the table without using “FOR UPDATE CLAUSE” but in that ... Read More
Problem: Is it possible to update a CURSOR in which we have used JOIN on 2 tables ORDERS and TRANSACTIONS? Why or why not? How can we proceed to UPDATE any of these tables?SolutionWhenever we use JOIN in a cursor on two or more tables (ORDERS and TRANSACTIONS in this case) a temporary table is generated in the virtual memory. However, since this is a temporary table we can fetch data from this table but it is not possible to update this table.If we want to update any of the tables used in the JOIN then we have to declare ... Read More
This example demonstrates how to call OnDestroy Activity in an Android App using Kotlin?Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport android.os.Bundle import android.util.Log import android.widget.Toast import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() { private val myTag = "Destroy" override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) title = "KotlinApp" ... Read More
Problem: A COBOL-DB2 program is changed to increase the length of a variable from PIC X(5) to PIC X(8). However, there are no changes in the SQL of the program. What will be the result if the program's plan/package is not binded for these changes?SolutionThe variable length change from PIC X(5) to PIC X(8) is not a DB2 change and there are no modifications required for SQL statements in the program. However, still we need to BIND its PLAN/PACKAGE else we will get SQL error code -818 which states that “THE PRECOMPILER-GENERATED TIMESTAMP x IN THE LOAD MODULE IS DIFFERENT ... Read More
Problem: The DB2 program PROGA was changed and compiled, but it was binded after 3 days. What will happen if we execute this program on the 4th day?SolutionThe pre-compiler inserts the current timestamp in the modified source code and in DBRM. In case of modified source code, this timestamp is passed on to the load module and in case of DBRM the timestamp is passed on to the package. At the time of program execution, the timestamp of load module and package is compared. This comparison takes place to ensure that the correct version of package and load module is ... Read More
Problem: Give and explain the panel command to display all the components of DB2 database DSNDB01 along with their status.SolutionA DB2 is a relational database which can be visualized to have both physical as well as logical structures. The physical structure contains components like log files, bufferpools, control files etc. On the other logical structure contains components like tablespace, indexspace, tables, views, packages, plans, etc.The components of physical structure have restricted access and only DBAs can access those files. However, it is possible for us to view components of logical structure using any of the below 2 options.Using DB2 administration ... Read More
This example demonstrates how to get the current date and time from the internet in Android using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport android.os.Bundle import android.widget.Button import android.widget.TextView import androidx.appcompat.app.AppCompatActivity import java.text.SimpleDateFormat import java.util.* class MainActivity : AppCompatActivity() { lateinit var calendar: Calendar lateinit var simpleDateFormat: SimpleDateFormat lateinit var date: String lateinit ... Read More
Packages are DB2 database objects which hold the executable forms of SQLs which are used in COBOL-DB2 programs. The packages are stored in a catalog table and contain the strategy/tables/columns/predicate associated with the SQL statements.If there is a DB2 table ORDERS_TEST in test environment and ORDERS_PROD in production environment, then we need two versions of COBOL-DB2 program (which will access these tables) — one for test and the other for production.Although both programs will be carbon copy of each other, the only difference lies in the SQL statements. The test version of the program will use table ORDERS_TEST in SQL ... Read More
This example demonstrates how to write files to the assets folder in android using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport android.os.Bundle import android.widget.Button import android.widget.TextView import androidx.appcompat.app.AppCompatActivity import java.io.IOException import java.io.InputStream class MainActivity : AppCompatActivity() { lateinit var textView: TextView lateinit var button: Button override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) ... Read More
When the COBOL-DB2 source code is given as an input in the pre-compilation stage, we get 2 important components — DBRM and modified source code.In modified source code, the SQL statements are replaced by COBOL calls and the DBRM contains all the SQL statements which are present in the COBOL-DB2 program. The pre-compiler inserts the timestamp in both DBRM and modified source code.In case of DBRM bind directly to the plan, the system compares the timestamp of the DBRM and load module when the COBOL-DB2 program is executed. In case there is a mismatch in the timestamp the JCL step ... Read More