1. Ch7. SQL for DB construction and Application Processing 데이터베이스시스템 (ND352)
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2. Chapter Objectives
To be able to create and manage table structures using SQL statements
To understand how referential integrity actions are implemented in SQL statements
To be able to create and use SQL constraints
To understand several uses for SQL views
To be able to use SQL statements to create and use views
To gain an understanding of how SQL is used in an application program
To understand how to create and use triggers
To understand how to create and use stored procedures
ND352 Database Systems - Prof. Ki-Hyung Hong

3. View Ridge Gallery
View Ridge Gallery is a small art gallery that has been in business for 30 years.
It sells contemporary European and North American fine art.
View Ridge has one owner, three salespeople, and two workers.
View Ridge owns all of the art that it sells; it holds no items on a consignment basis.
ND352 Database Systems - Prof. Ki-Hyung Hong

4. Application Requirements
View Ridge application requirements:
Track customers and their artist interests
Record gallery’s purchases
Record customers’ art purchases
List the artists and works that have appeared in the gallery
Report how fast an artist’s works have sold and at what margin
Show current inventory in a Webpage
ND352 Database Systems - Prof. Ki-Hyung Hong

5. View Ridge Gallery Database Design
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6. SQL DDL and DML Query (Select) : part of DML
ND352 Database Systems - Prof. Ki-Hyung Hong

7. Creating a New Database
in MySQL
create schema dbname;
drop schema dbname;
ALTER SCHEMA `vrg2` DEFAULT CHARACTER SET euckr ;
ND352 Database Systems - Prof. Ki-Hyung Hong

8. Create Table CREATE TABLE statement is used for creating relations.
Each column is described with three parts: column name, data type, and optional constraints.
Create Table NewTablename (
ColumnName DataType OptionalConstraint, …
optional table constraint );
ND352 Database Systems - Prof. Ki-Hyung Hong

9. Data Types (MySQL)
ND352 Database Systems - Prof. Ki-Hyung Hong

10. Constraints
Constraints can be defined within the CREATE TABLE statement, or they can be added to the table after it is created using the ALTER table statement.
Five types of constraints:
PRIMARY KEY may not have null values
UNIQUE may have null values
NULL/NOT NULL
FOREIGN KEY
CHECK
ND352 Database Systems - Prof. Ki-Hyung Hong

11. in MySQL Workbench
ND352 Database Systems - Prof. Ki-Hyung Hong

12. Create Table ARTIST ..
CREATE TABLE ARTIST ( ArtistID Int NOT NULL AUTO_INCREMENT, LastName Char(25) NOT NULL, FirstName Char(25) NOT NULL, Nationality Char(30) NULL, DateOfBirth Numeric(4) NULL, DateDeceased Numeric(4) NULL, CONSTRAINT ArtistPK PRIMARY KEY(ArtistID), CONSTRAINT ArtistAK1 UNIQUE(LastName, FirstName), CONSTRAINT NationalityValues CHECK (Nationality IN ('Canadian', 'English', 'French', 'German', 'Mexican', 'Russian', 'Spanish', 'United States')), CONSTRAINT BirthValuesCheck CHECK (DateOfBirth < DateDeceased), CONSTRAINT ValidBirthYear CHECK (DateOfBirth LIKE '[1-2][0-9][0-9][0-9]'), CONSTRAINT ValidDeathYear CHECK (DateDeceased LIKE '[1-2][0-9][0-9][0-9]') ); ALTER TABLE WORK AUTO_INCREMENT = 500;
ND352 Database Systems - Prof. Ki-Hyung Hong

13. Surrogate Key Column definition set initial value
ArtistID Int NOT NULL AUTO_INCREMENT,
set initial value
ALTER TABLE WORK AUTO_INCREMENT = 500;
Primary Key
CONSTRAINT ArtistPK PRIMARY KEY(ArtistID),
ND352 Database Systems - Prof. Ki-Hyung Hong

14. Create Table WORK ..
CREATE TABLE WORK ( WorkID Int NOT NULL AUTO_INCREMENT, Title Char(35) NOT NULL, Copy Char(12) NOT NULL, Medium Char(35) NULL, Description Varchar(1000) NULL DEFAULT 'Unknown provenance', ArtistID Int NOT NULL, CONSTRAINT WorkPK PRIMARY KEY(WorkID), CONSTRAINT WorkAK1 UNIQUE(Title, Copy), CONSTRAINT ArtistFK FOREIGN KEY(ArtistID) REFERENCES ARTIST(ArtistID) ON UPDATE NO ACTION ON DELETE NO ACTION ); ALTER TABLE WORK AUTO_INCREMENT = 500;
ND352 Database Systems - Prof. Ki-Hyung Hong

15. ON UPDATE/DELETE clause
ON UPDATE NO ACTION (default)
update to the primary key for a table that has children (foreign keys) should be prohibited.
ON UPDATE CASCADE
update to the primary key should be cascade to the children
FOREIGN KEY(ArtistID)
REFERENCES ARTIST(ArtistID)
ON UPDATE NO ACTION
ON DELETE NO ACTION
ND352 Database Systems - Prof. Ki-Hyung Hong

16. Implementing Cardinalities
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17. Implementing Default Values
Description Varchar(1000) NULL DEFAULT 'Unknown provenance',
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18. implementing Data Constraints
CHECK
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19. ALTER statement
ALTER statement changes table structure, properties, or constraints after it has been created.
Example
ALTER TABLE ASSIGNMENT
ADD CONSTRAINT EmployeeFK
FOREIGN KEY (EmployeeNumber)
REFERENCES EMPLOYEE (EmployeeNumber)
ON UPDATE CASCADE
ON DELETE NO ACTION;
ND352 Database Systems - Prof. Ki-Hyung Hong

20. Adding and Dropping Columns
The following statement will add a column named MyColumn to the CUSTOMER table:
ALTER TABLE CUSTOMER ADD MyColumn Char(5) NULL;
You can drop an existing column with the statement:
ALTER TABLE CUSTOMER DROP COLUMN MyColumn;
ND352 Database Systems - Prof. Ki-Hyung Hong

21. Adding and Dropping Constraints
ALTER can be used to add a constraint as follows:
ALTER TABLE CUSTOMER
ADD CONSTRAINT MyConstraint CHECK
([Name] NOT IN ('Robert No Pay'));
ALTER can be used to drop a constraint:
DROP CONSTRAINT MyConstraint;
ND352 Database Systems - Prof. Ki-Hyung Hong

22. Removing Tables If there are constraints: SQL DROP TABLE:
DROP TABLE TRANS;
If there are constraints:
ALTER TABLE CUSTOMER_ARTIST_INT
DROP CONSTRAINT Customer_Artist_Int_CustomerFK;
ALTER TABLE [TRANSACTION]
DROP CONSTRAINT TransactionCustomerFK;
DROP TABLE CUSTOMER;
ND352 Database Systems - Prof. Ki-Hyung Hong

23. SQL DML—INSERT INSERT command: Bulk INSERT:
INSERT INTO ARTIST ([Name], Nationality, DateOfBirth, DateDeceased)
VALUES ('Tamayo', 'Mexican', 1927, 1998);
Bulk INSERT:
INSERT INTO ARTIST
([Name], Nationality, DateOfBirth)
SELECT [Name], Nationality, Birthdate
FROM IMPORTED_ARTIST;
ND352 Database Systems - Prof. Ki-Hyung Hong

24. SQL DML-UPDATE UPDATE command: Bulk UPDATE: UPDATE CUSTOMER
SET City = 'New York City'
WHERE CustomerID = 1000;
Bulk UPDATE:
UPDATE CUSTOMER
SET AreaCode = '333'
WHERE City = 'Denver';
ND352 Database Systems - Prof. Ki-Hyung Hong

25. SQL DML—DELETE DELETE command:
DELETE FROM CUSTOMER
WHERE CustomerID = 1000;
If you omit the WHERE clause, you will delete every row in the table.
What is the difference between the following 2 SQL statements?
DELETE FROM CUSTOMER;
DROP TABLE CUSTOMER;
ND352 Database Systems - Prof. Ki-Hyung Hong

26. JOIN ON Syntax JOIN ON syntax: SELECT CUSTOMER.Name, ARTIST.Name
FROM CUSTOMER JOIN CUSTOMER_ARTIST_INT
ON CUSTOMER.CustomerID =
CUSTOMER_ARTIST_INT.CustomerID
JOIN ARTIST
ON CUSTOMER_ARTIST_INT.ArtistID =
ARTIST.ArtistID;
ND352 Database Systems - Prof. Ki-Hyung Hong

27. Using Aliases Use of aliases: SELECT C.Name, A.Name FROM CUSTOMER AS C
JOIN
CUSTOMER_ARTIST_INT AS CI
ON C.CustomerID = CI.CustomerID
JOIN ARTIST AS A
ON CI.ArtistID = A.ArtistID;
ND352 Database Systems - Prof. Ki-Hyung Hong

28. Outer Joins (vs. Inner Joins)
find customers who have never made any purchase at the gallery.
Left Outer Join:
SELECT C.LastName, C.FirstName,
A.LastName AS ArtistName
FROM CUSTOMER C LEFT
JOIN
CUSTOMER_ARTIST_INT CI
ON C.CustomerID = CI.CustomerID
LEFT JOIN ARTIST A
ON CI.ArtistID = A.ArtistID;
ND352 Database Systems - Prof. Ki-Hyung Hong

29. Result of Outer Join
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30. SELECT T. LastName, T. FirstName From (SELECT C. LastName, C
SELECT T.LastName, T.FirstName From (SELECT C.LastName, C.FirstName, A.LastName AS ArtistName FROM CUSTOMER C LEFT JOIN CUSTOMER_ARTIST_INT CI ON C.CustomerID = CI.CustomerID LEFT JOIN ARTIST A ON CI.ArtistID = A.ArtistID) AS T Where ArtistName is null;
ND352 Database Systems - Prof. Ki-Hyung Hong

31. Right Outer Join
Select C.LastName, C.FirstName, T.TransactionID, T.SalesPrice From Customer AS C RIGHT JOIN TRANS AS T ON C.CustomerID = T.CustomerID ORDER BY T.TransactionID;
ND352 Database Systems - Prof. Ki-Hyung Hong

32. SQL Views
SQL view is a virtual table that is constructed from other tables or views.
It has no data of its own, but obtains data from tables or other views.
SELECT statements are used to define views:
A view definition may not include an ORDER BY clause.
SQL views are a subset of the external views:
They can be used only for external views that involve one multivalued path through the schema.
ND352 Database Systems - Prof. Ki-Hyung Hong

33. Uses of SQL Views
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34. CREATE VIEW Command CREATE VIEW command: Results:
CREATE VIEW CustomerNameView AS
SELECT LastName AS
CustomerLastName,
FirstName AS
CustomerFirstName
FROM CUSTOMER;
Results:
SELECT *
FROM CustomerNameView
ORDER BY CustomerLastName,
CustomerFirstName;
ND352 Database Systems - Prof. Ki-Hyung Hong

35. Updateable Views
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36. Embedding SQL in Program Code
SQL can be embedded in triggers, stored procedures, and program code.
Problem: assigning SQL table columns with program variables.
Solution: object-oriented programming, PL/SQL.
Problem: paradigm mismatch between SQL and application programming language:
SQL statements return sets of rows; an application works on one row at a time.
Solution: process the SQL results as pseudo-files.
ND352 Database Systems - Prof. Ki-Hyung Hong

37. Application Logic - MySQL
MySQL Server database application can be processed using:
Programming languages to invoke SQL Server DBMS commands
The MySQL Command Line utility to invoke database commands stored in .sql files
The MySQL Query Browser to invoke database commands stored in .sql files
Stored procedures
Triggers
ND352 Database Systems - Prof. Ki-Hyung Hong

38. Triggers
A trigger is a stored program that is executed by the DBMS whenever a specified event occurs on a specified table or view.
Three trigger types: BEFORE, INSTEAD OF, and AFTER:
Each type can be declared for Insert, Update, and Delete.
Resulting in a total of nine trigger types.
Oracle supports all nine trigger types.
SQL Server supports six trigger types (only for INSTEAD OF and AFTER triggers).
ND352 Database Systems - Prof. Ki-Hyung Hong

39. Triggers
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40. Firing Triggers When a trigger is fired, the DBMS supplies:
Old and new values for the update
New values for inserts
Old values for deletions
The way the values are supplied depends on the DBMS product.
Trigger applications include:
Providing default values
Enforce data constraints
Updating views
Performing referential integrity actions
ND352 Database Systems - Prof. Ki-Hyung Hong

41. Triggers - MySQL
An SQL Server trigger is invoked when a specified database activity occurs.
Triggers can be used to:
Enforce business rules.
Set complex default values.
Update views.
Implement referential integrity actions.
MySQL Server only supports BEFORE and AFTER triggers.
Without the INSTEAD OF trigger, triggers on SQL views are not supported.
MySQL trigger support is very limited, and triggers may not be used to:
Make a change in the table that fired the trigger.
Return an output value—triggers can use the LEAVE keyword to exit without returning a value.
Make implicit or explicit ROLLBACKs of COMMITs.
ND352 Database Systems - Prof. Ki-Hyung Hong

42. Create Trigger – MySQL (p307)
DELIMITER //
CREATE TRIGGER AfterTRANSInsertSetAskingPrice
AFTER INSERT ON TRANS
FOR EACH ROW
BEGIN
DECLARE varRowCount Int;
DECLARE varPriorRowCount Int;
DECLARE varWorkID Int;
DECLARE varTransactionID Int;
DECLARE varAcquisitionPrice Numeric(8,2);
DECLARE varNewAskingPrice Numeric(8,2);
DECLARE varSumNetProfit Numeric(8,2);
DECLARE varAvgNetProfit Numeric(8,2);
SET varTransactionID = NEW.TransactionID;
SET varAcquisitionPrice = NEW.AcquisitionPrice;
SET varWorkID = NEW.WorkID;
ND352 Database Systems - Prof. Ki-Hyung Hong

43. Create Trigger – MySQL (p307)
# First find if work has been here before.
SELECT COUNT(*) INTO varRowCount
FROM TRANS
WHERE WorkID = varWorkID;
SET varPriorRowCount = (varRowCount - 1);
# If varPriorRowCount = 0 this is a new acquistion.
IF (varPriorRowCount = 0) THEN
# to twice the acquisition cost.
SET varNewAskingPrice = (2 * varAcquisitionPrice);
ELSE
# The work has been here before
# We have to determine the value of varNewAskingPrice
ND352 Database Systems - Prof. Ki-Hyung Hong

44. Create Trigger – MySQL (p307)
SELECT SUM(NetProfit) INTO varSumNetProfit
FROM ArtistWorkNetView AS AWNV
WHERE AWNV.WorkID = varWorkID
GROUP BY AWNV.WorkID;
SET varAvgNetProfit = (varSumNetProfit / varPriorRowCount);
# Now choose larger value for the new AskingPrice.
IF ((varAcquisitionPrice + varAvgNetProfit)
> (2 * varAcquisitionPrice)) THEN
SET varNewAskingPrice = (varAcquisitionPrice + varAvgNetProfit);
ELSE
SET varNewAskingPrice = (2 * varAcquisitionPrice);
END IF;
ND352 Database Systems - Prof. Ki-Hyung Hong

45. Create Trigger – MySQL (p307)
# Update PRICELIST with the value of AskingPrice
INSERT INTO PRICELIST VALUES (varTransactionID, 0);
UPDATE PRICELIST
SET AskingPrice = varNewAskingPrice
WHERE TransactionID = varTransactionID;
END //
DELIMITER ;
ND352 Database Systems - Prof. Ki-Hyung Hong

46. Application Logic: MySQL Statement Delimiters
MySQL must use a delimiter other than the SQL semicolon(;) when creating stored procedures and triggers:
This is a semicolon (;)
ND352 Database Systems - Prof. Ki-Hyung Hong

47. Application Logic: MySQL Control of Flow Statements
BEGIN…END
IF…ELSE…END
REPEAT
WHILE
ROLLBACK
This is a semicolon (;)
ND352 Database Systems - Prof. Ki-Hyung Hong

48. Application Logic: MySQL Cursor Statements
DECLARE
OPEN
FETCH
CLOSE CURSOR
DEALLOCATE CURSOR
ND352 Database Systems - Prof. Ki-Hyung Hong

49. Application Logic: MySQL Output Statements
MySQL does not have output statements such as PRINT.
Can use an SQL SELECT query to provide limited output
ND352 Database Systems - Prof. Ki-Hyung Hong

50. Stored Procedures
A stored procedure is a program that is stored within the database and is compiled when used:
In Oracle, it can be written in PL/SQL or Java.
In SQL Server, it can be written in TRANSACT-SQL.
Stored procedures can receive input parameters and they can return results.
Stored procedures can be called from:
Programs written in standard languages, e.g., Java, C#.
Scripting languages, e.g., JavaScript, VBScript.
SQL command prompt, e.g., SQL Plus, Query Analyzer.
ND352 Database Systems - Prof. Ki-Hyung Hong

51. Stored Procedures - MySQL
A stored procedure is a compiled program stored within the database.
Stored procedures are programs that can:
Have parameters
Invoke other procedures and functions
Return values
Raise exceptions
Creating stored procedures:
Write a stored procedure in a text file and process the commands using the MySQL Query Browser
ND352 Database Systems - Prof. Ki-Hyung Hong

52. Stored Procedure Advantages
Greater security as store procedures are always stored on the database server
Decreased network traffic
SQL can be optimized by the DBMS compiler
Code sharing resulting in:
Less work
Standardized processing
Specialization among developers
ND352 Database Systems - Prof. Ki-Hyung Hong

53. ND352 Database Systems - Prof. Ki-Hyung Hong

54. ND352 Database Systems - Prof. Ki-Hyung Hong

55. Call Stored Procedure
CALL InsertCustomerAndInterests ('Bench', 'Michael', '206', 'French'); SELECT * FROM CustomerInterestsView ORDER BY CustomerLastName, CustomerFirstName;
ND352 Database Systems - Prof. Ki-Hyung Hong

56. Triggers vs. Stored Procedures
ND352 Database Systems - Prof. Ki-Hyung Hong