Chapter 8: Managing Schema Objects

Purpose

A schema is a collection of database objects. A schema is owned by a database user and has the same name as that user. Schema objects are logical structures created by users to contain, or reference, their data. Schema objects include structures like tables, views, and indexes. You can create and manipulate schema objects using Oracle Enterprise Manager.

Time to Complete

Approximately 1 hour

Topics

This tutorial covers the following topics:

	Prerequisites
	Accessing Schema Objects
	Managing Tables
	Managing Indexes
	Managing Views
	Managing Database Resident Program Units
	Loading Data into Tables
	Summary

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Prerequisites

Before you perform this tutorial, you should:

1.	Complete Chapter 2: Installing Oracle Software and Building the Database OBE
2.	Complete Chapter 3: Getting Started with Oracle Enterprise Manager OBE
3.	Complete Chapter 4: Configuring the Network Environment OBE
4.	Complete Chapter 5: Managing the Oracle Instance OBE
5.	Complete Chapter 6: Managing Database Storage Structures OBE
6.	Complete Chapter 7: Administering Users and Security OBE

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Accessing Schema Objects

Follow the steps below to access schema objects using Enterprise Manager:

1.	Log in to Enterprise Manager Database Control by opening your browser and specifying the SYS username and password. Click Login.
2.	Click Schema and select the Tables link in the Database Objects section.
3.	Click the flashlight icon to select a particular schema.
4.	Select HR and click Select.
5.	Enter emp in the Object Name field and click Go.
6.	The objects that match your search criteria are displayed.

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Managing Tables

Tables are the basic unit of data storage in an Oracle database. They hold all user-accessible data. Each table has columns and rows. In this section, you will perform the following tasks:

A	Viewing the Attributes of a Table
B.	Viewing the Contents of a Table
C.	Creating a New Table
D.	Modifying a Table
E.	Dropping a Table

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Viewing the Attributes of a Table

Follow the steps below to view the attributes of the HR.EMPLOYEES table:

Click the EMPLOYEES table link.

The View Table page appears displaying the attributes of the table including columns, constraints, and storage options.

Click the Tables link to return to the Tables property page.

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Viewing the Contents of a Table

Perform the steps listed below to view the contents of the HR.EMPLOYEES table:

Select the EMPLOYEES table and select View Data from the Actions list. Click Go.

The View Data for Table page appears showing the row data in the Result section. Click the Tables link to return to the Tables property page.

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Creating a New Table

In this section you will create three new tables for your database: EMPLOYEES, CUSTOMERS, and ORDERS.

Click Create on the Tables property page.

The Create Table: Table Organization page appears. Select Standard, Heap Organized and click Continue.

The Create Table page appears. Enter employees in the Name field. Enter fsowner in the Schema field. Enter fsdata in the Tablespace field. Define the columns as follows and click Add 5 Table Columns.

Name: EMPLOYEE_ID, Data Type: NUMBER, Size: 6
Name: FIRST_NAME, Data Type: VARCHAR2, Size: 20
Name: LAST_NAME, Data Type: VARCHAR2, Size: 25
Name: EMAIL_ADDRESS, Data Type: VARCHAR2, Size: 25
Name: PHONE_NUMBER, Data Type: VARCHAR2, Size: 20

Enter the remaining columns as follows:

HIRE_DATE DATE
JOB_ID VARCHAR2(10)
SALARY NUMBER(8)
MANAGER_ID NUMBER(6)

Click Constraints.

The Constraints page appears. Select PRIMARY from the drop-down list and click Add.

The Add PRIMARY Constraint page appears. Enter emp_id_pk in the Name field. Select EMPLOYEE_ID in the Available Columns list. Click Move to select it. Click Continue.

The Create Table page appears. Click OK.

The Tables page appears with an Update message indicating your table has been created.

Repeat steps 2 through 8 to create the CUSTOMERS and ORDERS tables in the FSOWNER schema as defined below. Name the primary key for the Customers table, CUST_ID_PK, and for the Orders table, ORD_PK_ID.

CUSTOMERS
Column	Type	PK?
CUSTOMER_ID	NUMBER(6)	Y
CUST_FIRST_NAME	VARCHAR2(20)
CUST_LAST_NAME	VARCHAR2(20)
STREET_ADDRESS	VARCHAR2(40)
CITY	VARCHAR2(30)
STATE	VARCHAR2(10)
POSTAL_CODE	VARCHAR2(10)
PHONE_NUMBER	VARCHAR2(20)

ORDERS
Column	Type	PK?
ORDER_ID	NUMBER(12)	Y
ORDER_DATE	DATE
ORDER_MODE	VARCHAR2(8)
CUSTOMER_ID	NUMBER(6)
DELIVERY_MODE	VARCHAR2(8)
ORDER_STATUS	NUMBER(2)
SALES_CLERK_ID	NUMBER(6)
ORDER_TOTAL	NUMBER(8,2)

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Modifying a Table

You can use Enterprise Manager to modify tables, such as adding and deleting columns or adding constraints. In this section you will add a constraint to the EMPLOYEES table you created. You will ensure that the EMAIL_ADDRESS column contains a value by adding a NOT NULL constraint.

Follow the steps below to add a NOT NULL constraint to your EMPLOYEES table:

Select the EMPLOYEES table and click Edit.

Check the Not NULL column for the EMAIL_ADDRESS column. Click Apply.

The Edit Table page is displayed with a message confirming your update.

Click the Tables link to return to the Tables page.

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Dropping a Table

You can drop (delete) a table by using Enterprise Manager as follows. For the purposes of this exercise, you will create a new table and then drop the table.

1.	Click the Tables link in the Database Objects section on the Schema page to access the Tables property page. Enter HR in the Schema Name field and JOBS in the Object Name field. Click Go.
2.	Select Create Like from the Actions list. Click Go.
3.	The Create Table page appears. Enter JOBS_HIST in the Name field. Deselect Not Null for the JOB_ID and JOB_TITLE columns. Click Constraints.
4.	The Constraints page appears. Delete the constraints on the table by selecting each and clicking Delete. They are not needed for this exercise. Click General to return to the General page.
5.	Click OK to create the JOBS_HIST table.
6.	A message is displayed indicating that the table has been created.
7.	Scroll to the bottom of the page and select the JOBS_HIST table.
8.	Click Delete With Options to the delete the JOBS_HIST table.
9.	Select Delete the table definition, all its data, and dependent objects. Click Yes.
10.	A message is displayed indicating the table has been deleted. Enter jobs_hist in the Object Name field and click Go to attempt to retrieve the table again.
11.	No object found is displayed in the results section indicating your table has been dropped (deleted). Click the Database Instance link to return to the Schema page.

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Managing Indexes

Indexes are optional structures associated with tables and can be used to improve query performance. An index provides a quick access path to table data. Indexes can be created on one or more columns of a table. After an index is created, it is automatically maintained and used by the Oracle Database server. Changes to a table’s data or structure are automatically incorporated into all relevant indexes with complete transparency to the user.

In this section, you will perform the following tasks:

A	Viewing the Attributes of an Index
B.	Creating a New Index

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Viewing the Attributes of an Index

Perform the steps listed below to view the attributes of an index in your FSOWNER schema:

1.	Click the Indexes link in the Database Objects section on the Schema page to access the Indexes property page.
2.	The Indexes page appears. Enter FSOWNER in the Schema field and click Go.
3.	The indexes created when you defined primary keys are displayed. Select the EMP_ID_PK index defined on the EMPLOYEES table by clicking the index name link.
4.	The View Index page for EMP_ID_PK index in the FSOWNER schema is displayed. Click the Indexes link to return to the Indexes property page.

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Creating a New Index

Create an index on the CUSTOMER_ID column in the ORDERS table so that you can quickly access all orders for a specified customer. The index should be stored in the FSINDEX tablespace.

Perform the steps listed below to create the ORD_CUSTID_IDX index:

Select Table from the Object Type list. The page is refreshed. Enter FSOWNER in the Schema field and click Go.

The Tables page appears. Select the ORDERS table and select Create Index from the Actions list. Click Go.

The Create Index page appears. Enter ORD_CUSTID_INDX in the Name field. Enter fsdata in the Tablespace field. Select Standard - B-tree as the index type. Select the CUSTOMER_ID column by entering 1 in the Order column. Accept ASC as the Sorting Order. Click OK to create the index.

You receive a message that the index was created. Click the Database Instance link to return to the Schema page.

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Managing Views

Views are customized presentations of data in one or more tables or other views. They can be thought of as stored queries. Views do not actually contain data, but instead they derive their data from the tables upon which they are based. These tables are referred to as the base tables of the view. Like tables, views can be queried, updated, inserted into, and deleted from, with some restrictions. All operations performed on a view actually affect the base tables of the view. Views provide an additional level of security by restricting access to a predetermined set of rows and columns of a table. They also hide data complexity and store complex queries.

In this section, you will perform the following tasks:

A	Accessing Views
B.	Creating a New View

Accessing Views

Perform the steps listed below to access views:

1.	Select Views in the Database Objects section of the Schema page.
2.	On the Views property page, enter HR in the Schema field and click Go.
3.	The views defined on tables in the HR schema are displayed. Select the EMP_DETAILS_VIEW and click View to view its definition.
4.	The View page is displayed showing the definition of the view. Click the Views link to return to the Views page.

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Creating a New View

Perform the steps listed below to create a new view:

Click Create on the Views property page.

Enter the following information and click OK.

View name: CLERK10_ORDS
Schema: FSOWNER
Query text:

SELECT order_id, customer_id, order_total FROM orders WHERE sales_clerk_id = 10

The Views page is displayed confirming the creation of your view.

Click the Database Instance link to return to the Schema page.

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Managing Database Resident Program Units

You can use Enterprise Manager to manage database resident program units such as PL/SQL packages, procedures, triggers, and functions and Java sources and classes. The actions include creating and compiling the database resident program units, creating synonyms for the database resident program units, granting privileges to use the database resident program units, and showing dependencies for the database resident program units.

1.	Click the Procedures link in the Programs section on the Schema page.
2.	Enter hr in the Schema field. Click Go.
3.	Select the ADD_JOB_HISTORY procedure. Select Object Privileges from the Actions list and click Go.
4.	Click Add.
5.	Select EXECUTE as the privilege and FSOWNER as the user. Click OK.
6.	Click Apply.
7.	You receive a confirmation message. Click the Database tab to return to the Database Home page.

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Loading Data Into Tables

You can use Enterprise Manager to load data into tables in batch. Batch loading is useful when you have a lot of data. You can load data from operating system files or from other databases. You can also export data into files. One method of loading is to use control (.ctl) and data (.dat) files. These files are formatted as standard SQL*Loader files. SQL*Loader is a utility that you can use to load data from external files into tables of an Oracle database.

In this section you will load customer information into your FSOWNER.CUSTOMERS table using the load_cust.ctl file. Create a directory named $HOME/labs. Download the load_cust.zip file and unzip the load_cust.ctl and load_cust.dat files into $HOME/labs for use in this section.

1.	Click the Load Data from User Files link in the Move Row Data section on the Data Movement page.
2.	The Load Data: Generate or Use Existing Control File page appears. Select Use Existing Control File. Also enter the username and password for the host machine. Click Continue. Enter the full path of your control file on the database server machine and click Next. (Note: For this example, you will use the control file included with the load_cust.zip file).
3.	The Load Data: Data File page appears. Select Provide the full path and name on the database server machine. Input the full path of your dat file on the database server machine. (Note: For this example, you will use the .dat file included with the load_cust.zip file).Click Next.
4.	The Load Data: Load Method page appears. Accept the default of Conventional Path as the loading method. Click Next.
5.	The Load Data: Options page appears. Select Generate log file in the Optional Files region. You can accept the default file name and path or enter a different one. Click Next.
6.	The Load Data: Schedule page appears. Enter a name in the Job Name field and description in the Description field. Select Immediately to run the job now. Click Next.
7.	The Load Data: Review page appears. Review your file names and loading methods. If you want to change something, you can click on the Back button. Otherwise, click Submit Job to start the loading.
8.	The Status page appears with a message indicating the job was created. Click the job name link to view the job summary.
9.	This summary page should indicate that the job has succeeded. If not, you can view the log file by clicking on your job under the Logs heading or by viewing the log file directly.
10.	You can confirm the data load by navigating to the Tables page, entering FSOWNER in the Schema field, clicking Go, selecting the table, and selecting View Data from the Actions list. Click Go.
11.	The rows you loaded are displayed on the View Data for Table: FSOWNER.CUSTOMERS page. Click OK to return to the Tables property page. Click Database to return to the Database Home page.

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Summary

In this tutorial, you learned how to:

	Query for tables in a specific schema.
	Create an table and view the attributes and contents of the new table.
	Create a view.
	Manage database resident program units.
	Load data into an existing table.

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