ORACLE SQL

Overview Personal DBMS Vs Client/Server DBMS Oracle 8 Environment SQL – syntax and examples PL/SQL-introduction

Server Gets file requests from clients Sends files to client Receives files back from clients NETWORK Client A Sends file requests to server Receives files from server Updates data Sends files back to server Client B Sends file requests to server Receives files from server Updates data Sends files back to server Personal DBMS

Personal DBMS - Problems Demand on the client and the network Does not perform table locking automatically Not fault tolerant in the case of client failure Do not have file based transaction logging

Server Gets data requests from clients Adds, Deletes and updates data Sends results to clients NETWORK Client A Sends data requests to server Receives results from server Sends new data or changes to server Client B Sends data requests to server Receives results from server Sends new data or changes to server Client/server DBMS

Client/Server DBMS Minimal load on the client and the network Performs table locking automatically Fault tolerant in the case of client failure File based transaction logging

Oracle 8 Environment SQL * Plus PL/SQL Query Builder Developer Enterprise Manager Web application server

Sqlplus username/password ALTER USER user-name IDENTIFIED BY newpassword START filename filename CLEAR SCREEN HELP HELP SAVE filename[.ext] REPLACE|APPEND EXIT SQL*Plus commands

SQL Both an ANSI and ISO standard Types of commands: 1. Data Definition Language (DDL) : Create, Alter, Drop, Rename, Truncate 2. Data Manipulation Language (DML): Insert, Delete, Update 3. Data Retrieval: Select 4. Transaction Control: Commit, Rollback, Savepoint 5. Data Control Language (DCL): Grant, Revoke

PositionIDPositionDescription 1President 2Manager 3Programmer 4Accountant 5Salesman QualificationIDQualificationDescription1Doctorate 2Masters 3Bachelors 4Associates DeptIDDeptNameLocation10FinanceCharlotte 20Infosys New York 30MarketingWoodbridge 40AccountantCalifornia DEPARTMENT POSITION QUALIFICATION

EmpIDLastNameFirstNamePositionIDSuperIDHireDateSalaryCommDeptIDQualID 111SmithJohn104/15/ HoustonLarry211105/19/ RobertsSandi211112/02/ McCallAlex354305/10/ DevDereck211103/15/ ShawJinku513501/03/ ChenSunny412308/15/ GarnerStanley211102/29/ EMPLOYEE

Data Definition Language: CREATE TABLE {table} ( {column datatype [DEFAULT expr] [column_constraint]... | table_constraint} [column_constraint]... | table_constraint} [, { column datatype [DEFAULT expr] [, { column datatype [DEFAULT expr] [column_constraint]... [column_constraint]...) ALTER TABLE {table} [ADD|MODIFY {column datatype [DEFAULT expr] [column_constraint]} [DROP drop_clause] DROP TABLE {table} [cascade constraints] DESC {table}

CREATE TABLE Emp ( empid Decimal(10) NOT NULL, empid Decimal(10) NOT NULL, positionid Number(2), positionid Number(2), supervisorid Number(3), supervisorid Number(3), deptid Number(2), deptid Number(2), qualid Number(1), qualid Number(1), lname varchar2(10), lname varchar2(10), fname varchar2(10), fname varchar2(10), salary Decimal(10,2), salary Decimal(10,2), hiredate Date, hiredate Date, commission Decimal(4,2), commission Decimal(4,2), PRIMARY KEY (empid), PRIMARY KEY (empid), FOREIGN KEY (positionid) REFERENCES Position(positionid), FOREIGN KEY (positionid) REFERENCES Position(positionid), FOREIGN KEY (deptid) REFERENCES Dept(deptid), FOREIGN KEY (deptid) REFERENCES Dept(deptid), FOREIGN KEY (qualid) REFERENCES Qualification(qualid) FOREIGN KEY (qualid) REFERENCES Qualification(qualid)); ALTER TABLE EMP MODIFY Commission decimal(7,2);

Data Manipulation Language: INSERT INTO {table | view} [ (column [, column]...) ] VALUES (expr,expr...) UPDATE {table | view } SET { (column [, column] = { expr | } [WHERE condition] DELETE [FROM] {table | view} [WHERE condition]

INSERT INTO Dept( deptid,deptname,location) VALUES(50,'IT','Dallas'); INSERT INTO Emp(empid, lname,fname,positionid, supervisorid,hiredate, salary,deptid,qualid) VALUES(227,'howser','Barbara',4,111,'25-AUG-83',45000,10,3); UPDATE dept SET deptname='Sales' WHERE deptID=50; DELETE FROM dept WHERE deptid='50';

Data Retrieval: SELECT [DISTINCT | ALL] {table|view} FROM {table | view} [WHERE condition ] [GROUP BY expr [, expr]] [ORDER BY {expr} [ASC | DESC]] select * from dept; select deptname from dept where deptid='10'; select lname,fname from emp order by lname desc; select max(salary) from emp group by positionid; select deptname from dept,emp where dept.deptid=emp.deptid and emp.empid='111'; dept.deptid=emp.deptid and emp.empid='111';

Transaction Control: COMMIT ROLLBACK [ to {savepoint}] SAVEPOINT {name} commit; savepoint point1; rollback to point1;

Data Control Language: GRANT [privileges] ON object TO user|public [WITH GRANT OPTION] REVOKE [privileges] ON object TO user|public [CASCADE CONSTRAINTS] grant select,update on emp to XYZ ; revoke update on emp to XYZ;

A PL/SQL Example: CREATE OR REPLACE PROCEDURE raise_salary (empno INTEGER, increase REAL) IS increase REAL) IS current_salary REAL; salary_missing EXCEPTION; BEGIN SELECT salary INTO current_salary FROM emp WHERE emp.empid = empno; IF current_salary IS NULL THEN RAISE salary_missing; ELSE UPDATE emp SET salary = salary + increase WHERE emp.empid = empno; END IF; EXCEPTION WHEN salary_missing THEN UPDATE emp SET salary=0 where emp.empid=empno; END raise_salary;