Chapter 6 SQL

Agenda Data Definition Language (DDL) Access Control

String Data Types Boolean data: true, false, null, unknown value (true > false) Character data –Fixed length: CHAR(4) –Variable length: VARCHAR(30) Bit data: binary string –BIT(4)

Numeric Data Types NUMERIC or NUMBER [precision, [scale]] DECIMAL or DEC [precision, [scale]] INTEGER or INT SMALLINT (32,767) FLOAT [precision] REAL DOUBLE PRECISION

Datetime data DATE: year, month, day TIME [timeprecision (for second, default=0)] [with time zone (control hour and minute)]: hour, minute, second TIMESTAMP [timeprecision (for second, default=6] [with time zone (control hour and minute)]: date and times

Integrity Enhancement Feature Required data Domain constraints Entity integrity Referential integrity Enterprise constraints

Required Data Position VARCHAR(10) NOT NULL

Domain Constraints - I CHECK (search condition) –sex CHAR(1) NOT NULL CHECK (sex IN (‘m’, ‘f’)) –credit AS NUMBER(3) CHECK (VALUE BETWEEN 0 AND 999) – major AS CHAR(3) DEFAULT ‘mis’ CHECK (VALUE IN (‘mis’, ‘man’, ‘act’, ‘obe’))

Domain Constraints - II CREATE DOMAIN domain name [AS] data type [DEFACULT default option] [CHECK (VALUE IN (search condition))] –CREATE DOMAIN sextype AS CHAR(1) DEFACULT ‘m’ CHECK (VALUE IN (‘m’,’f’)); –sex sextype NOT NULL –CREATE DOMAIN cnumber AS CHAR(2) CHECK (VALUE IN (SELECT cno FROM customer)); –cid cnumber NOT NULL DROP DOMAIN domain name [RESTRICT l CASCADE] –DROP DOMAIN cnumber;

Entity Integrity PRIMARY KEY key name or key names NOT NULL –PRIMARY KEY sno NOT NULL –sno INTEGER NOT NULL UNIQUE –PRIMARY KEY (sno, classno, sdate) NOT NULL

Referential Integrity Referential action for ON UPDATE and ON DELETE –CASCADE –SET NULL –SET DEFAULT –NO ACTION Examples –FOREIGN KEY hotelno REFERENCES hotel (hotelno) –FOREIGN KEY hotelno REFERENCES hotel (hotelno) ON DELETE SET NULL –FOREIGN KEY hotelno REFERENCES hotel (hotelno) ON UPDATE CASCADE

Enterprise Constraints Methods –CHECK clause –UNIQUE clause –CREATE ASSERTION statement CREATE ASSERTION assertion name CHECK (assertion condition) CREATE ASSERTION toomuch CHECK (NOT EXIST (SELECT sno FROM enroll GROUP BY sno HAVING COUNT (*) >10);

SQL DDL CREATE ALTER DROP

CREATE SCHEMA DOMAIN TABLE INDEX VIEW

ALTER TABLE DOMAIN

DROP SCHEMA DOMAIN TABLE INDEX VIEW

CREATE Schema CREATE SCHEMA [name | AUTHORIZATION creator-id] DROP SCHEMA name [RESTRICT | CASCADE] Examples –CREATE SCHEMA mis150 AUTHORIZATION tsai; –DROP SCHEMA mis150;

SQL DDL For Table CREATE TABLE table-name (colm data- type [NOT NULL][UNIQUE] [DEFAULT option][CHECK search- cond][,...],[PRIMARY KEY (colm [,colm])],[FOREIGN KEY (colm [,colm]) REFERENCES (parent-table)[colms])

Create A New Table Example CREATE TABLE student (stuid NUMBER(5) NOT NULL CHECK (stuid BETWEEN AND 99999), stuname CHAR(10), major CHAR(10), credit NUMBER(3), CONSTRAINT pkstudent PRIMARY KEY (stuid));

Create A New Table Example CREATE TABLE faculty (facid NUMBER (5) NOT NULL, facname CHAR(10), dept CHAR(10), rank CHAR(3) CHECK (rank IN (‘F’,’Aso’, ‘Ast’)), CONSTRAINT pkfaculty PRIMARY KEY (facid));

Create A New Table Example CREATE TABLE class (course# NUMBER(5) NOT NULL, facid NUMBER(5), sched CHAR(10), room CHAR(10), CONSTRAINT pkclass PRIMARY KEY (course#), CONSTRAINT fkclassfaculty FOREIGN KEY (facid) REFERENCES faculty (facid));

Create A New Table Example CREATE TABLE enrollment (course# NUMBER(5) NOT NULL, stuid NUMBER(5) NOT NULL, grade CHAR(10), CONSTRAINT pkenroll PRIMARY KEY (course#, stuid), CONSTRAINT fkenrollclass FOREIGN KEY (course#) REFERENCES class (course#), CONSTRAINT fkenrollstudent FOREIGN KEY (stuid) REFERENCES student (stuid));

SQL DDL For Table DROP TABLE table-name [RESTRICT | CASCADE]; ALTER TABLE table-name [ADD][MODIFY][COLUMN] colm data-type [NOT NULL][UNIQUE] [DEFAULT option][CHECK search- cond][,...][DROP [COLUMN]colm [RESTRICT|CASCADE]

Examples ALTER TABLE enrollment MODIFY (grade NUMBER(3)); ALTER TABLE enrollment ADD (datetake DATE not null); DROP TABLE enrollment;

SQL DDL For Table ALTER TABLE table-name [ADD [CONSTRAINT[constrnt-name]]table- constrnt][DROP CONSTRAINT constrnt-name][RESTRICT | CASCADE]

CREATE TABLE customer (lastname CHAR(20) NOT NULL, firstname CHAR(20) NOT NULL, customerid NUMBER(5) NOT NULL, address CHAR(10)); ALTER TABLE customer ADD (CONTRAINT pkcustomer PRIMARY KEY (lastname, firstname)); ALTER TABLE customer DROP CONSTRAINT pkcustomer; ALTER TABLE customer ADD (CONTRAINT pkcustomer PRIMARY KEY (customerid));

Example CREATE TABLE purchaseorder (ponumber CHAR (5) NOT NULL, podate DATE) CONTRAINT pkpurchasorder PRIMARY KEY (ponumber)); CREATE TABLE puchaseorderlineitem (ponumber CHAR(5) NOT NULL, lineitem CHAR(5) NOT NULL, quantity NUMBER(5) NOT NULL, CONTRAINT pkpuchaseorderlineitem PRIMARY KEY (ponumber, lineitem)); ALTER TABLE puchaseorderlineitem ADD (CONSTRAINT fkpolineitem FOREIGN KEY (ponumber) REFERENCES purchaseorder (ponumber)); ALTER TABLE puchaseorderlineitem DROP (CONSTRAINT fkpolineitem);

SQL DDL For Index CREATE [UNIQUE] INDEX index- name ON base-table-name (column [ASC | DESC] [,... ) DROP INDEX index-name

Examples CREATE INDEX studentname ON student (stuname DESC); CREATE INDEX majorcredit ON student (major, credit); DROP INDEX majorcredit;

SQL DDL For View CREATE VIEW view-name [(view- colm [,...])] AS SELECT... [WITH [CASCADE|LOCAL] CHECK OPTION] DROP VIEW view-name [RESTRICT | CASCADE]

Examples CREATE VIEW substudent (studentid, studentname, major) AS SELECT stuid, stuname, major FROM student; CREATE VIEW productprofit (productid, productname, profit) AS SELECT productid, productname, sale-cost FROM inventory; DROP VIEW productprofit;

Advantages of Views Data independence Currency Improved security Reduced complexity Convenience Customization Data integrity

Disadvantages of Views Update restriction Structure restriction Performance

Access Control GRANT system-privilege TO role-name GRANT object-privilege ON [owner.] object-name TO role-name GRANT role-name TO user-name REVOKE privilege FROM role-name REVOKE role-name FROM user-name

System Privileges CREATE TABLE CREATE VIEW CREATE USER ALTER INDEX

Object Privileges SELECT INSERT UPDATE DELETE

Examples GRANT CREATE TABLE, CREATE VIEW, CREATE USER TO manager; GRANT SELECT, INSERT, UPDATE, DELETE ON student TO manager; GRANT manger TO tsai;

REVOKE DELETE ON student FROM manager; REVOKE manager FROM tsai;

Points To Remember Structured Query Language (SQL) Data Definition Language (DDL) Access Control

Assignment Review chapters 1-4, 5, and appendix C Read chapters M-2, M-3 Homework assignment –6.10, 6.11(a, b, c, d), 6.12, 6.13, 6.14 –Due date: