Oracle_ch3.pptx

8/10/2019 Oracle_ch3.pptx

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Dr. Chen, Oracle Database System (Oracle) 1

Chapter 3:

Table Creation and Management:Creating and Modifying

Database Tables

Jason C. H. Chen, Ph.D.

Professor of MIS

School of Business Administration

Gonzaga University

Spokane, WA 99258

[email protected]


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Objectives

Become acquainted with Structured Query Language(SQL)

Identify the table name and structure

Create a new table using the CREATE TABLE command

Use a subquery to create a new table Add a column to an existing table

Modify the definition of a column in an existing table

Delete a column from an existing table

Mark a column as unused and then delete it at a later time Rename a table

Truncate a table

Drop a table


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Database Objects and Queries

An Oracle database consists of multiple user accounts

Each user account owns database objects Tables

Views

Stored programs, etc.

Query: command to perform operation on databaseobject

Structured Query Language (SQL) Industry standard query language for most of relational

databases

Consists of about 30 commands


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Basic SQL Concepts and Commands

SQL (Structured Query Language) is used to

manipulate the database.

There are twobasictypes of SQL commands:

DDL commands work with the structureof the objects

(tables, indexes, views) in the database.

DML commands work with the datain the database

(i.e.,manipulate the data).

Reserved words - SQL command words

Data Definition Language (DDL)

Data Manipulation Language (DML)


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Security -

Granting Table Privileges

Security is the prevention of unauthorized access

to the database. Within an organization, the

database administrator determines the types of

access various users need for the database. Some users might be able to retrieve and update

data in the database. Other users might be able to

retrieve any data from the database but not make

any changes to it. Still other users might be ableto access only a portion of the database.


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A. Names and PropertiesWhy need a name?


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Creating a Table

CREATE TABLE tablename

(fieldname1data_type (size),

fieldname2 data_type (size),

);


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Defining Oracle10g Database Tables

To create a table, you must specify:

Table name

Field names

Field data types

Field sizes

Constraints

restrictions on the data values that a field can store


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I. Names and Properties: Conventions

1. From 1 to 30 characters

2. Only alphanumeric characters, and special

characters ($ , _, #)3. Must begin with a letter and can not contain blank

spaces or hyphens

4. Must be unique and No reserved words are allowed

Series of rules Oracle Corporation established for

naming all database objects

Are the following names valid? Why?

customer order

customer-order

#order

Customer_#

Customer#


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Oracle 11g Data Types

Data typeSpecifies kind of data that column stores

Provides means for error checking

Enable DBMS to use storage space moreefficiently by internally storing different types of

data in different ways

Basic types

Character

Number

Date/time


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II. Data Types

Built-inprovided by the system

Librarybuilt by the software

vendor or a third party

User-definedbuilt by users


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Basic Built-In Data Types

Character VARCHAR2

CHAR

Numeric NUMBER

DATE

OTHERS: LOB, BLOB, LONG, RAW, LONG RAW


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Character Data Types

1. VARCHAR2

Stores variable-length character data upto a maximum of 4,000 characters

Values in different records can have adifferent number of characters

fieldname VARCHAR2(maximum_size)

(e.g.) emp_name VARCHAR2(20); an instance: Jason Chen


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Character Data Types (cont.)

2. CHAR

Fixed-length character data (


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Character Subtypes

Examples:

VARCHAR2(5) Smith or Smi

CHAR(5) Smith or Smi

LONG Smith...

Note that you do not specify a size for

LONG.

To include a single quote in a literal

character string, use two in a row:

This is Heralds string.


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Question: Which query will possibly generatestudent information?

What data type should be used if there is any

chance that all column spaces will NOT be filled?

Answer: VARCHAR2

s_Last VARCHAR2(15);

SELECT s_Last, s_First,

s_AddressFROM student

WHERE s_Last = Smith;

s_Last CHAR(15);

SELECT s_Last, s_First,

s_AddressFROM student

WHERE s_Last = Smith;

L


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When use Query:

SELECT s_last, s_first, ssn, telephoneFROM student

WHERE s_last = Smith;

Case is sensitive within the single

quotation.

SQL Plus commands are NOTcasesensitive, but Query within the single

quotation are case sensitive.


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3. Number Data Types

Stores negative, positive, fixed, and floating pointnumbers between

10 -130


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Number Data Types (examples)

a) Integer: Number (n) e.g. s_id NUMBER(5)

12345

b) Fixed-point numbers

e.g. current_price NUMBER (5, 2); 259.99 33.89

c) Fixed-point numbers (cont.)

e.g. total_mileage NUMBER (5, 1);

259.9 33.8 d) Floating-point Numberwith a variable number of

decimal places

e.g. s_gpa NUMBER;

3.89 2.7569 3.2


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4. Date and Time Data Types

Date, time data subtypes Store actual date and time values

DATE

Dates from December 31, 4712 BC to December 31, 4712

AD Default format DD-MON-YY

Default time format HH:MI:SS A.M.

fieldnameDATE

Sample declaration: OrderDate DATENOT NULL;

Use one of the following format masks: TO_DATE( , MM/DD/YY)

TO_DATE( , DD-MON-YYYY)

TO_DATE( , HH:MI AM

)


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Table Design (continued)

Table 3-2 Oracle 11g Datatypes


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Table Creation

Column definition list must be enclosed in

parentheses Datatype must be specified for each column

Maximum of 1,000 columns

Defining Columns

Figure 3-1 CREATE TABLE syntax


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acctmanager

Exercise: Create a new table of acctmanager based on

the following information

CREATE TABLE

(

NOTNULL);

Amid Amfirst Amlast AmeDate Amsal Amcomm Region

VARCHAR2(4) VARCHAR2(12) VARCHAR2(12) DATE NUMBER(8,2) NUMBER(7,2) CHAR(2)

GROUP WORK

Complete the

CREATE command

manually!

acctmanager

amid


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acctmanager

Exercise: Create a new table of acctmanager based on

the following information

CREATE TABLE

(

amfirst VARCHAR2(12) NOT NULL,

amlast VARCHAR2(12) NOT NULL,

amedate DATE DEFAULT SYSDATE,

amsal NUMBER(8,2),amcomm NUMBER(7,2) DEFAULT 0,

region CHAR(2) NOT NULL);

Amid Amfirst Amlast AmeDate Amsal Amcomm Region

VARCHAR2(4) VARCHAR2(12) VARCHAR2(12) DATE NUMBER(8,2) NUMBER(7,2) CHAR(2)

SELECT *

FROM acctmanager;

acctmanager

amid VARCHAR2(4) PRIMARY KEY,


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Refresh the Database

1. Create a new folder on c:\ as follows:

c:\oradata\chapter3

2. Go to Blackboard and download data

files from Oracle chapter3 and save under

c:\oradata\chapter3\

3. Run the following script file

Start c:\oradata\chapter3\JLDB_Build_3.sql


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ExerciseYour Turn

Type the following commands:1) SELECT TABLE_NAME FROM USER_TABLES;

2) DROP TABLE ACCTMANAGER CASCADE

CONSTRAINTS;

3) DROP TABLE ACCTMANAGER2 CASCADE

CONSTRAINTS;

4) SELECT TABLE_NAME FROM USER_TABLES;

You now are able to create acctmanagertable


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CREATE TABLE Command Example

Virtual Column/

(Derived/computed)

Figure 3-2 The creation of the ACCTMANAGER table

What is the difference

between these two versions:

Is this a good approach?


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Viewing Table Structures: DESCRIBE

DESCRIBE displays the structure of a specified table

Figure 3-4 The DESCRIBE command


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Table Creation through Subqueries

You can use subqueries to retrieve datafrom an existing table

Requires use of AS keyword

New column names can be assigned

CREATE TABLEAS

Figure 3-8 CREATE TABLE AS command syntax


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CREATE TABLEAS Command

Example

Figure 3-7 Creating a table based on a subquery

SELECT * FROM cust_mkt;


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ALTER TABLEADD Command

Figure 3-12 The ALTER TABLE ADD command


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ALTER TABLEMODIFY Command

Figure 3-18 The ALTER TABLE MODIFY command to increase the column width


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Modification Guidelines

Column must be as wide as the data it

already contains

If a NUMBER column already contains

data, size cannot be decreased

Adding or changing default data does not

affect existing data


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ALTER TABLESET UNUSED Command

Once marked for deletion, a column cannot berestored

Storage space is freedat a later time

36


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ALTER TABLEDROP UNUSED Command

Frees up storage space from columns previouslymarked as unused

However, once a table is set UNUSED it cant be

DROPPED using the following (regular) command:ALTER TABLE tablename

DROP COLUMN colname; Show: test_UNUSED.sql

and test_UNUSED.doc


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AuthorID LName FName

VARCHAR2(4) VARCHAR2(10) VARCHAR2(10)

AUTHOR

SQL> SELECT * FROM author;

AUTH LNAME FNAME

---- ---------- ----------

S100 SMITH SAM

J100 JONES JANICE

A100 AUSTIN JAMES

M100 MARTINEZ SHEILA

K100 KZOCHSKY TAMARAP100 PORTER LISA

A105 ADAMS JUAN

B100 BAKER JACK

P105 PETERSON TINA

W100 WHITE WILLIAM

W105 WHITE LISA

AUTH LNAME FNAME

---- ---------- ----------

R100 ROBINSON ROBERT

F100 FIELDS OSCAR

W110 WILKINSON ANTHONY

14 rows selected.

AUTHOR


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AUTHOR

SQL> describe author;Name Null? Type

------------ -------- ---------------

AUTHORID NOT NULL VARCHAR2(4)

LNAME VARCHAR2(10)

FNAME VARCHAR2(10)

SQL>

SQL> ALTER TABLE author SET UNUSED

COLUMN fname;

Table altered.

SQL> describe author;

Name Null? Type

----------- -------- -------------

AUTHORID NOT NULL VARCHAR2(4)LNAME VARCHAR2(10)

SQL>

SQL> ALTER TABLE author DROP COLUMN

lname;

Table altered.

SQL>ALTER TABLE author DROP COLUMN

fname;

ALTER TABLE author DROP COLUMN fname

*

ERROR at line 1:

ORA-00904: "FNAME": invalid identifier

SQL> ALTER TABLE author

2 DROP UNUSED COLUMNS;

Table altered.

SQL> describe author;

Name Null? Type

----------- -------- -------------

AUTHORID NOT NULL VARCHAR2(4)

SQL>

Show: test_UNUSED.sql

and test_UNUSED.doc

AUTHOR


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AUTHOR

SQL> SELECT * FROM author;

AUTH

----

A100

A105

B100

F100

J100K100

M100

P100

P105

R100

S100

AUTH

----

W100

W105

W110

14 rows selected.


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Practice all the rest of examples in the text.

A Script file is available on the Bb (file

name: Ch3Queries.sql)

After completing all examples, do the HW.

H k H d O A i


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Homework - Hands-On Assignments

Read and Practice all examples on Chapters 3

1. Run the script files (in the folder \oradata\chapter3\):

JLDB_Build_3.sql 2. Read Oracle assignment and create a script file

Oracle_ch3_Lname_Fname.sql for questions (#1 to#8; p.94)on Hands-on Assignments. .

3. Execute and test one problem at a time and make surethey are all running successfully.

4. When you done, spool the script files (see next slidefor spooling instructions) and email the file(Oracle_ch3_Spool_Lname_Fname.txt) to me by themidnight before the next class. Turn in a hardcopy to mein the class.

Email me with one attachment

(Oracle_ch3_Spool_Lname_Fname.) to:

[email protected] subject title of

bmis441_Oracle_ch3


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How to Spool your Script and Output Files

After you tested the script file of Oracle_ch3_Lname_Fname.sql successfully,follow the instructions below to spool both script and output files:

Step 0. Run the following script file from SQL*Plus (since you have createdJLDB tables)

Start c:\oradata\chapter3J\LDB_Build_3.sql

1. type the following on SQL> Spool c:\oradata\Oracle_ch3_Spool_Lname_Fname.txt(make sure your name is entered)

2. open Oracle_ch3_Lname_Fname.sql that you already tested 3. copy and paste all the SQL commands (including all comments) to the

SQL*PLUS

4. type Spool Off on the SQL>

The output should contain your personal information, all SQL commands and

their solution on the .txt file and saved in C: drive (oradata\ folder)

Email me with the spooled file (.txt) with attachment to:

[email protected]

with subject title of

bmis441_Oracle_ch3


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End of chapter 3

Documents

Oracle_ch3.pptx