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Chapter Nine Data Manipulation Language (DML)Views

Objectives Definition Creating views Retrieve data from a view Drop a view

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VIEWSDATABASE OBJECTS

1-TABLE2-VIEW

-What is a view?-Why using a view?

Restrict database access.Make complex queries easy.Represent data from different

tablesRepresent different Views of the

same data.

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CREATE VIEW COSCStudent AS

SELECT ID, Name, GPAFROM StudentWHERE Major=‘COSC’;

DESCRIBE COSCStudent;

VIEWSDATABASE OBJECTS

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Practice:Create a view called Customer_v with the attributes:

-Customer number-Customer last name-Customer Street-Customer City-Customer State -Customer zip code

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Practice:Create a view for customer sales person called Cust_Sale_v with the attributes:

-Customer number-Customer last name-Sales Rep Number-Sales Person First Name-Sales Person Last Name

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Aliases Column Name:CREATE VIEW COSCStudent

ASSELECT ID COSCid,

name COSCName,GPA

FROM StudentWHERE Major=‘COSC’;

VIEWSDATABASE OBJECTS

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Retrieving Data from View:SELECT *FROM COSCStudent;

SELECT COSCid, COSCnameFROM COSCStudent;

VIEWSDATABASE OBJECTS

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Practice:Display all the fields in Cust_Sale_v

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Example:CREATE VIEW COSCData

(minsal, maxsal, avesal)AS

SELECT MIN(salary), MAX (salary), AVG (salary)

FREOM facultyWHERE dept =‘COSC’;

VIEWSDATABASE OBJECTS

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Practice:Create a view called Cust_v with the attributes:

-Customer number-Customer name (Last, First)-Customer Address (Street, city, state, zip)-Customer balance-Customer credit limit-Sales Rep Number

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Removing a View:DROP VIEW majors;

VIEWSDATABASE OBJECTS

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Practice:Remove the view Cust_v

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Practice:Create a view using a sub-query.