4 Copyright © 2004, Oracle. All rights reserved. Database Interfaces.

4Copyright © 2004, Oracle. All rights reserved.

Database Interfaces

4-2 Copyright © 2004, Oracle. All rights reserved.

Objectives

After completing this lesson, you should be able to do the following:

• Use SQL*Plus and iSQL*Plus to access the Oracle Database 10g

• Describe the logical structure of tables

• Use SQL to query, manipulate, and define data

• Identify common database interfaces


What Is SQL?

SQL provides statements for a variety of tasks, including:

• Querying data

• Inserting, updating, and deleting rows in a table

• Creating, replacing, altering, and dropping objects

• Controlling access to the database and its objects

SQL unifies all of the preceding tasks in one consistent language.


Using SQL

There are several tools for interfacing with the database using SQL:

• Oracle SQL*Plus and iSQL*Plus

• Oracle Forms, Reports, and Discoverer

• Oracle Enterprise Manager

• Third-party tools


Enterprise Manager: Seeing the SQL


What Is SQL*Plus?

• Command-line tool

• Used interactively or in batch mode

$ sqlplus /nologSQL*Plus: Release 10.1.0.2.0 - Production on Tue Feb 17 06:17:14 2004Copyright (c) 1982, 2004, Oracle. All rights reserved.SQL> connect ricEnter password:Connected.SQL> SELECT * FROM dual;

D-XSQL>


What Is iSQL*Plus?


Using iSQL*Plus


Describing Data


Querying Data

The SELECT has three basic parts:

• The SELECT List

• The FROM clause

• The WHERE condition (optional)


Sorting the Data

SQL> SELECT last_name, department_id, phone_number 2 FROM employees 3 ORDER BY last_name;

LAST_NAME DEPARTMENT_ID PHONE_NUMBER--------------- ------------- --------------------Abel 80 011.44.1644.429267Ande 80 011.44.1346.629268Atkinson 50 650.124.6234Austin 60 590.423.4569Baer 70 515.123.8888Baida 30 515.127.4563Banda 80 011.44.1346.729268


Joining Tables

Getting data from more than one table


Manipulating Data

SQL> INSERT INTO employees 2 (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER, 3 HIRE_DATE,JOB_ID,SALARY,COMMISSION_PCT, 4 MANAGER_ID,DEPARTMENT_ID) 5 VALUES 6 (9999,'Bob','Builder','[email protected]',NULL,sysdate, 7 'IT_PROG’,NULL,NULL,100,90);

1 row created.

SQL> UPDATE employees SET SALARY=6000 2 WHERE EMPLOYEE_ID = 9999;

1 row updated.

SQL> DELETE from employees 2 WHERE EMPLOYEE_ID = 9999;

1 row deleted.


Defining Data


Overview of Transactions

Transaction 1 Transaction 2COMMIT;


Transaction Control Statements

SQL> SELECT * FROM local_temp;no rows selected

SQL> INSERT INTO local_temp VALUES 2 (SYSDATE, 76, 58);1 row created.

SQL> SELECT * from local_temp;TEMP_DATE HI_TEMP LO_TEMP--------- ---------- ----------27-OCT-03 76 58

SQL> ROLLBACK;Rollback complete.

SQL> SELECT * FROM local_temp;no rows selected


Locking Data

Oracle Database 10g automatically locks data so that only one user can make changes at a time.


Other Statement Categories

• Session control statements: Manage the properties of a user session

• System control statement: Manages the properties of an Oracle instance

• Embedded SQL statements: SQL statements within a procedural language program


What Is PL/SQL?

PL/SQL is a block-structured language, which extends SQL with:

• Declarations:– Variables– Constants– Cursors

• Control structures:– Conditional control– Iterative control– Sequential control

• Error handling


Example PL/SQL Block

DECLARE qty_on_hand NUMBER(5);BEGIN SELECT quantity INTO qty_on_hand FROM inventory WHERE product = 'TENNIS RACKET' FOR UPDATE OF quantity; IF qty_on_hand > 0 THEN -- check quantity UPDATE inventory SET quantity = quantity - 1 WHERE product = 'TENNIS RACKET'; INSERT INTO purchase_record VALUES ('Tennis racket purchased', SYSDATE); ELSE INSERT INTO purchase_record VALUES ('Out of tennis rackets', SYSDATE); END IF; COMMIT;END;


Uses of PL/SQL

Blocks of PL/SQL are used in:

• Anonymous blocks

• Functions

• Procedures

• Packages

• Triggers

• Object types


What Is Java?

Java is an industry-standard, object-oriented programming language. It includes the following concepts:

• A Java Virtual Machine (JVM), which provides platform independence

• Automated storage management techniques

• Language syntax that borrows from C and enforces strong typing


Oracle and Java

A PL/SQL function:

CallableStatement cstmt = conn.prepareCall("{? = CALL balance(?)}"); cstmt.registerOutParameter(1, Types.FLOAT); cstmt.setInt(2, acctNo); cstmt.executeUpdate();float acctBal = cstmt.getFloat(1);

FUNCTION balance (acct_id NUMBER) RETURN NUMBER ISacct_bal NUMBER;BEGIN SELECT bal INTO acct_bal FROM accts WHERE acct_no = acct_id; RETURN acct_bal;END;

Calling the function with Java:


What Is OCI?

OCI provides for:

• The Oracle Call Interface (OCI) is how all database features are made accessible to application developers.

• OCI makes scalable and high-performance applications possible.

• Higher-level APIs and tools use OCI indirectly for database access.


Other APIs

• Java Database Connectivity (JDBC)

• Pro*C/C++

• Pro*COBOL

• Oracle C++ Interface (OCCI)

• Open Database Connectivity (ODBC)

• Oracle Data Provider for .NET (ODP.NET)

• Oracle Objects for OLE (OO4O)


Summary

In this lesson, you should have learned how to:

• Use SQL*Plus and iSQL*Plus to access Oracle Database 10g

• Describe the logical structure of tables

• Use SQL to query, manipulate, and define data

• Identify common database interfaces


Practice 4: Using SQL

This practice covers using iSQL*Plus to:

• Describe tables

• Select from tables

• Update a table

• Delete from a table

• Undo changes

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