Oracle SQL Plus The Definitive Guide- P4 pot

Page 10The Data Model Figure 1-2 shows an Entity Relationship Diagram, or ERD, for the sample database.. The sample database As you can see from the ERD, there are only three entities: E

Page 10

The Data Model

Figure 1-2 shows an Entity Relationship Diagram, or ERD, for the sample database.

Figure 12

The sample database

As you can see from the ERD, there are only three entities: EMPLOYEE, PROJECT, and PROJECT_HOURS Table 12 gives a brief description

of each entity.

Table 12 Entity Descriptions

Entity Name Description

EMPLOYEE Contains one record for each employee This record contains the employee's name, hire date, termination date,

and billing rate The primary key is an arbitrary employee ID number The termination date for current employees is set to NULL.

PROJECT Contains one record for each project that an employee may work on Contains the project name and budget The

primary key is an arbitrary project ID number.

PROJECT_HOURS Each time an employee logs time to a project, a record is generated in this table The record contains the number

of hours charged against the project as well as the total dollar amount charged The dollar amount charged is calculated at the time the record is created because an employee's billing rate may fluctuate over time The primary key is a combination key made up of an employee ID, a project ID, and the date.

The number of employees and projects is fairly small However, there is a fairly large amount of data in the PROJECT_HOURS table to allow for the generation of

multiple page reports, which are needed to demonstrate pagination, page headings, page footings, and summarization.

The Tables

This section shows the column descriptions, including column datatypes and lengths, for each of the three sample

tables This is the same information you would get using SQL*Plus's DESCRIBE command

The EMPLOYEE table

Name Null? Type

- -

EMPLOYEE_ID NOT NULL NUMBER

EMPLOYEE_NAME VARCHAR2(40)

EMPLOYEE_HIRE_DATE DATE

EMPLOYEE_TERMINATION_DATE DATE

EMPLOYEE_BILLING_RATE NUMBER

The PROJECT_HOURS table

NAME NULL? TYPE

- -

PROJECT_ID NOT NULL NUMBER

PROJECT_NAME VARCHAR2(40)

PROJECT_BUDGET NUMBER

The PROJECT_HOURS table

NAME NULL? TYPE

- -

PROJECT_ID NOT NULL NUMBER

EMPLOYEE_ID NOT NULL NUMBER

TIME_LOG_DATE NOT NULL DATE

HOURS_LOGGED NUMBER

DOLLARS_CHARGED NUMBER

The Data

This section shows the data contained in the three sample tables

The EMPLOYEE table

ID Name Hire Date Term Date Billing Rate

- - - - -

101 Jonathan Gennick 15-Nov-1961 Still Employed 169.00

102 Jenny Gennick 16-Sep-1964 05-May-1998 135.00

104 Jeff Gennick 29-Dec-1987 01-Apr-1998 99.00

105 Horace Walker 15-Jun-1998 Still Employed 121.00

107 Bohdan Khmelnytsky 02-Jan-1998 Still Employed 45.00

108 Pavlo Chubynsky 01-Mar-1994 15-Nov-1998 220.00

110 Ivan Mazepa 04-Apr-1998 30-Sep-1998 84.00

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111 Taras Shevchenko 23-Aug-1976 Still Employed 100.00

112 Hermon Goche 15-Nov-1961 04-Apr-1998 70.00

113 Jacob Marley 03-Mar-1998 31-Oct-1998 300.00

The PROJECT table

ID Project Name Budget

- - -

1001 Corporate Web Site 1,912,000.00

1002 Year 2000 Fixes 999,998,000.00

1003 Accounting System Implementation 897,000.00

1004 Data Warehouse Maintenance 294,000.00

1005 TCP/IP Implementation 415,000.00

The PROJECT_HOURS table

The PROJECT_HOURS table contains the following information, repeated for each employee

Proj ID Emp ID Log Date Hours Charged Amt Charged

- - - - -

1001 101 01-Jan-1998 1.00 169.00

1003 101 01-Jan-1998 3.00 507.00

1005 101 01-Jan-1998 5.00 845.00

1002 101 01-Feb-1998 7.00 1,183.00

1004 101 01-Feb-1998 1.00 169.00

1001 101 01-Mar-1998 3.00 507.00

1003 101 01-Mar-1998 5.00 845.00

1005 101 01-Mar-1998 7.00 1,183.00

1002 101 01-Apr-1998 1.00 169.00

1004 101 01-Apr-1998 3.00 507.00

1001 101 01-May-1998 5.00 845.00

1003 101 01-May-1998 7.00 1,183.00

1005 101 01-May-1998 1.00 169.00

1002 101 01-Jun-1998 3.00 507.00

1004 101 01-Jun-1998 5.00 845.00

1001 101 01-Jul-1998 7.00 1,183.00

1003 101 01-Jul-1998 1.00 169.00

1005 101 01-Jul-1998 3.00 507.00

1002 101 01-Aug-1998 5.00 845.00

1004 101 01-Aug-1998 7.00 1,183.00

1001 101 01-Sep-1998 1.00 169.00

1003 101 01-Sep-1998 3.00 507.00

1005 101 01-Sep-1998 5.00 845.00

1002 101 01-Oct-1998 7.00 1,183.00

1004 101 01-Oct-1998 1.00 169.00

1001 101 01-Nov-1998 3.00 507.00

1003 101 01-Nov-1998 5.00 845.00

1005 101 01-Nov-1998 7.00 1,183.00

1002 101 01-Dec-1998 1.00 169.00

1004 101 01-Dec-1998 3.00 507.00

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sonable summary reports, as you will see in Chapter 3, Generating Reports with SQL*Plus.

Loading the Sample Data

In order to load the sample data you will need an Oracle userid and password If you are accessing a remote database, often the case for people using Windows, you will also need a connect string If you are using Oracle Personal Edition (formerly Personal Oracle), then the connect string is not needed to connect to your local database You must have the necessary privileges and quotas to create tables in the database you are using Specifically, you must have the following system privileges:

CREATE SESSION

ALTER SESSION

CREATE TABLE

CREATE VIEW

CREATE TRIGGER

CREATE PROCEDURE

CREATE SYNONYM

CREATE SEQUENCE

CREATE TYPE (Oracle8 only)

Your database administrator can help you with any of these items Once you have a username and password and have been granted the necessary privileges, you can create the sample tables and data by following these four steps:

1 Download and unzip the script files

2 Start SQL*Plus

3 Log into your Oracle database

4 Run the BLD_DB.SQL script file.

The screenshots in the remainder of this section show you how things would look if you were creating the sample tables and data using SQL*Plus in a Windows 95 or NT environment Under other operating systems, such as Unix,

everything would look much the same, except that SQL*Plus may not have its own window and the userid/password prompts may not be in a dialog box

If you are new to SQL*Plus and are completely uncertain how to start it in your particular environment, you should first

read the section titled Starting SQL*Plus in Chapter 2, Interacting with SQL*Plus Once you know how to start

SQL*Plus, you can come back here and run the script to create the sample tables and fill them with data

Step 1: Download and unzip the script files

The SQL scripts to create the tables and data used for the examples in this book can be downloaded from O'Reilly & Associates' web site See the Preface for more information

The scripts are stored in a ZIP file named BLD_DB.ZIP Download this file, and extract the contents into a directory on your hard disk If you do not have an unzip utility, you may download BLD_DB.EXE instead BLD_DB.EXE is a

selfextracting ZIP file Just run it, the scripts will be extracted, and you won't need a separate unzip utility

Step 2: Start SQL*Plus

When you first start SQL*Plus in a Windows environment, you will see a SQL*Plus window open You will also

immediately be prompted for a userid, a password, and a host string Your screen should look like the one shown in Figure 13

Figure 13

SQL*Plus immediately after startup

On a Unix system, you won't see a dialog box like that shown in Figure 13 Instead you will simply see a userid prompt

Step 3: Log into your Oracle database

Type your userid, password, and host string into the three dialog box fields If you are using Oracle Personal Edition, you typically leave the host string field blank Once the correct information is entered, click the OK button If you are using a Unix system, answer the username prompt by typing in your username and

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ing ENTER Answer the password prompt in the same way Once logged in, you should see a screen similar to that shown in Figure 14

Figure 14

SQL*Plus after a successful login The opening screen shows the SQL*Plus version, some copyright information, and some Oracle database version

information The exact version numbers and options you see may vary from those shown in Figure 14

Step 4: Run the BLD_DB.SQL script file

The next and final step is to run the BLD_DB.SQL script file, which is one of the files in the ZIP archive you

downloaded in step 1 To do that, simply use the @ command as shown below:

SQL> @c:\ \bld_db

You need to specify the full directory path to this file

After you type in the above command and press ENTER, your SQL*Plus screen should look like the one shown in Figure 15

The first thing the script does is confirm that you really do want to load the sample data Go ahead and answer with a Y,

or with an N if you've changed your mind about loading the data

You must answer the script questions with either a Y or an N Your reply is not case-sensitive, so a lowercase response is fine Input validation is minimal, but it is there If you give an invalid response, an error message will be displayed and the script will stop You will then need to restart the script, using the START command as shown earlier, and answer correctly

Figure 15

After the BLD_DB script is started

If you've answered Y to the question about continuing, the next thing you will see is another prompt asking if you want

to first drop the sample tables This is shown in Figure 16

This option to first drop the sample tables is convenient if you have loaded them before and wish to quickly reload them If this is your first time running this script,

you should answer this question with an N If you have loaded the tables previously, and you know that they exist now, then you should answer with a Y

Now you can just sit back and watch The next thing the script does is create the sample tables Following that it inserts data into each table Figure 17 shows the progress messages being displayed on the screen while all this is occurring

Figure 17

Progress messages from the BLD_DB script The entire load process should take less than a minute When the load is complete, you will be asked to press ENTER one final time After doing that, you can use the EXIT command to exit SQL*Plus

Now that you have loaded the sample data, you can proceed with the book and try out the examples as you go