1. SQL for Database Construction and Application Processing
Chapter 7
SQL for Database Construction and
Application Processing

2. First create the database

3. New types of SQL statements

4. SQL vs Graphical tools Quicker
Facilitates recreation of same tables needed by applications
Some applications need you to create temporary tables which require SQL code
SQL is standardized and DBMS independent
Except for some data types
Point 2: when reporting, querying, and data mining

5. Tables from View Ridge Database Design of Chapter 6
Identity specifies surrogate key (starting at 1, incrementing by 1)
Identity (500,1) specifies surrogate key starting at 100 going up by 1
Identity works for SQL Server. Oracle, MySQL and ACCESS use different techniques
Everything in this chapter runs on SQL Server

6. SQL code to create
Constarints define the primary key, and a candidate or alternate key.
Primary purpose of alternate keys Is to ensure uniqueness of column values; thus alternate keys are defined using the UNIQUE command
Each column is defined by giving its name, data type and null status. If you do not specify, NULL is assumed
Numeric (4,0) means a 4 digit number with zero places to the right of the decimal point.
Primary keys must be NOT NULL
Candidate keys can be NULL or NOT NULL
SQL statements are not case sensitive – upper case is historical from punch card era
Commas are separators
Statements are terminated by semicolons

7. Data Type Reminder – SQL Server

8. Data Type Reminder – Oracle

9. Let’s try to create the WORK table

10. WORK. ArtistID must exist in ARTIST
WORK.ArtistID must exist in ARTIST.ArtistID is equivalent to foreign key constraint above
DELETE CASCADE would cascade deletions
DELETE NO ACTION is the default

11. Table creation and deletion order
Create parents before children
Delete children before parents

12. Relationship Definitions

13. What would the default values & data constraints be for View Ridge?
Table
Name
Column
Default Value
Constraint
WORK
title
copy
original
ARTIST
DeceasedDate
DeceasedDate must follow BirthDate
ArtistID
Can’t be null
Name must be unique
Nationality
Angola
Birthdate
birthDate has to precede current date; birthdate must precede deceasedDate

14. CHECK CONSTRAINTS Similar to SQL WHERE
IN – provides list of valid values
NOT IN – for negatively expressed constraints
LIKE – used for specification of decimal values

15. Results

16. ALTER statements
ALTER statement changes table structure, properties, or constraints after it has been created

17. Examples ALTER TABLE ASSIGNMENT
ADD CONSTRAINT EmployeeFK FOREIGN KEY (EmployeeNum)
REFERENCES EMPLOYEE (EmployeeNumber)
ON UPDATE CASCADE
ON DELETE NO ACTION;
ALTER TABLE CUSTOMER ADD MyColumn Char(5) NULL;
ALTER TABLE CUSTOMER DROP COLUMN MyColumn;

18. More ALTER examples DROP TABLE [TRANSACTION];
ALTER TABLE CUSTOMER ADD CONSTRAINT MyConstraint CHECK ([Name] NOT IN ('Robert No Pay'));
ALTER TABLE CUSTOMER DROP CONSTRAINT MyConstraint;
DROP TABLE [TRANSACTION];

19. More ALTER examples ALTER TABLE CUSTOMER_ARTIST_INT
DROP CONSTRAINT Customer_Artist_Int_CustomerFK;
ALTER TABLE [TRANSACTION]
DROP CONSTRAINT TransactionCustomerFK;
DROP TABLE CUSTOMER;

20. INSERT examples INSERT INTO ARTIST ([Name], Nationality, Birthdate,
DeceasedDate)
VALUES ('Tamayo', 'Mexican', 1927, 1998);
INSERT INTO ARTIST ([Name], Nationality, Birthdate)
SELECT [Name], Nationality, Birthdate
FROM IMPORTED_ARTIST;