Oracle: Programs

1. 1 Using ORACLE® MANIPULATING DATA using PL/SQL

2. 2 COMMENTING CODE We can add comments to the PL/SQL .There are two types of comments: EXAMPLE: DECLARE eage NUMBER ; --This is a single line comment . number variable defined. BEGIN SELECT age INTO eage FROM InfoTable WHERE name = ‘bill’; /* A multiline command .Here the select command is defined */ END

3. 3 FUNCTIONS The functions available in SQL can be used in PL/SQL code. Not all SQL function can be used in PL/SQL statements .The SQL functions unavailable in Pl/SQL statements are: DECODE function. All GROUP functions except the LEAST and GREATEST. EXAMPLE1: ename VARCHAR2(20) := INITCAP(‘bill’); --stores Bill in the variable ename. We can use data type conversion function in PL/SQL statements. EXAMPLE 2: mainphone NUMBER(10) := 9000000000; ename VARCHAR2(20); BEGIN SELECT name INTO ename FROM InfoTable WHERE phone = TO_NUMBER(mainphone); END

4. 4 Operators in PL/SQL

5. 5 Operators EXAMPLES: profit BOOL; sp NUMBER; cp NUMBER; BEGIN cp:= 1000; sp:= 1200; profit := ((sp – cp) > 100); -- finding if profit was above 100 or not END

6. 6 RETRIEVING DATA We can retrieve data using the SELECT command. Variables are used to store the values returned from the SELECT statement and hence have to be of the same datatype and be declared before use. SYNTAX: SELECT column, […column] INTO variable_name,[…variable_name] FROM table_name WHERE { expression….}; EXAMPLE: DECLARE eage NUMBER; BEGIN SELECT age INTO eage FROM InfoTable WHERE name = ‘bill’; DBMS_OUTPUT.PUT_LINE(‘ Age of bill is : ‘ || eage); END

7. 7 INSERT command We can insert data into tables using the PL/SQL INSERT command. SYNTAX: INSERT INTO table_name (column , (…..column)) VALUES (value , (…..value)); EXAMPLE: BEGIN INSERT INTO InfoTable (name,age,phone) VALUES (‘micheal’,45,9666002203); END

8. 8 UPDATE command We can update data in tables using the PL/SQL UPDATE comand. SYNTAX: UPDATE table_name SET column = value, (…column = value); WHERE {expression }; EXAMPLE: DECLARE eage NUMBER(5):=40; BEGIN UPDATE InfoTable SET age = eage WHERE name = ‘micheal’; END

9. 9 DELETE command We can delete data from tables using the PL/SQL DELETE comand. SYNTAX: DELETE FROM table_name WHERE { expression }; EXAMPLE: BEGIN DELETE FROM InfoTable WHERE age = 45 ; END

10. 10 MERGE COMMAND The MERGE comand is use to merge the data of one table into the data of another table.The merge command updates or inserts rows in order to make data in both rows similar. DECLARE ename INFOTABLE.NAME%TYPE := ‘bill'; BEGIN MERGE INTO addtable a USING infotable I Infotable ON (i.name =ename) WHEN MATCHED THEN UPDATE SET a.phone = i.phoneADDtable WHEN NOT MATCHED THEN INSERT VALUES(i.name,NULL,i.phone); END; ADDtable after MERGE

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