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The document discusses the Data Manipulation Language (DML) in SQL. It describes the INSERT, UPDATE, and DELETE commands. INSERT is used to add new rows, UPDATE changes existing rows by specifying conditions in a WHERE clause, and DELETE removes rows specified in a WHERE clause. Examples are provided for each command demonstrating how to insert single and multiple rows, update fields by condition, and delete rows based on conditions.
![DML COMMANDS
Insert- Insert is used to add a new row to a table
SYNTAX :
INSERT INTO tablename [(field list)] VALUES (value list)
Field list is optional
If field list is omitted, values expected for all columns (except IDENTITY)
INSERT](https://image.slidesharecdn.com/dmlslide-151216005536/85/database-slide-4-320.jpg)
database slide
- 2. INTRODUCTION SQL (Structured Query Language) is the standard language used for the manipulation and accessing databases. SQL is divided into two parts : 1. DML (Data Manipulation Language) 2. DDL (Data Definition Languagae)
- 4. DML COMMANDS Insert- Insert is used to add a new row to a table SYNTAX : INSERT INTO tablename [(field list)] VALUES (value list) Field list is optional If field list is omitted, values expected for all columns (except IDENTITY) INSERT
- 5. INSERT SINGLE ROW EXAMPLES 1.INSERT INTO Students(StudentID) VALUES(‘s01’) 2.INSERT INTO Courses(Department, CourseNumber) VALUES(‘CS’,’C01’) 3.INSERT INTO Courses VALUES(‘CS’,’C01’,’SQL Projects’,5,)
- 6. ASSIGNING NULL VALUES If Null is acceptable for a column Omit field from field list; Or Use NULL in Value list Assume Course description is optional: INSERT INTO Courses VALUES(‘CIS’,’282’,’SQL Projects’,5,Null) INSERT INTO Courses(Department, CourseNumber, Title, Credits) VALUES(‘CIS’,’282’,’SQL Projects’,5)
- 7. UPDATE Update is used to change an existing row Can change one, some or all rows in a table or view A WHERE clause is used to specify specific rows to change Multiple conditions require a logical operator SYNTAX : UPDATE tablename SET field1 = value1,field2 = value2 WHERE field=value
- 8. UPDATE EXAMPLES Assign value to zip code for 2nd publisher: UPDATE publishers SET pub_zip = 20006 WHERE pub_id = 0877 Change publisher name to add ‘Ltd.’ for any Massachusetts publisher: UPDATE publishers SET pub_name = pub_name + ‘Ltd.’ WHERE pub_state = ‘ma’
- 9. DELETE Delete removes one or more rows from the table No field list is included May specify which rows to remove by adding WHERE clause Delete Syntax DELETE FROM tablename WHERE condition
- 10. DELETE EXAMPLES DELETE FROM Publishers WHERE pub_state <>’ca’ DELETE FROM Publishers WHERE pub_zip IS NULL OR pub_state = ‘wa’ DELETE FROM Publishers