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Chapters 21, 22, 23, 37

Ch. 21: SQL*Loader

Ch. 22: Database Links, Oracle Net

Ch. 23: Materialized Views (aka Snapshots)

Ch. 37: Data Dictionary

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Ch. 21: SQL*Loader

SQL*Loader loads data from external files into tables in Oracle.

Usually requires 2 primary files: • Datafile(s), data to be loaded.

• Control file, describes how to load.

• these two files can be combined into the control file.

When executing, SQL*Loader creates:• bad file, shows rejected rows

• log file, shows load status

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Ch. 21: SQL*Loader Control File Examples Variable field control file

Fixed field control file

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Ch. 22: Database Links Database links allow you to access data in another Oracle database. Requires that Oracle Net (aka Oracle SQL*Net or Net8) be running on

both database servers. Links specify:

• Protocol (eg. TCP/IP)• Host name of remote server.• Database name on the remote server• The database account and password to access the data.

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Ch. 22: Database Links Create Database Link syntax:

CREATE DATABASE LINK MYLINKCONNECT TO ATEAL IDENTIFIED BY PASSWORDUSING ‘PHOENIX’;

Using a database link:SELECT COUNT(*) FROM ATEAL.MYTABLE@MYLINK;

Using a synonym with a database link:CREATE SYNONYM MYTABLE FOR ATEAL.MYTABLE@MYLINK;SELECT COUNT(*) FROM MYTABLE;

“Dynamic” links using SQL*Plus’s copy command:COPY FROM ATEAL/PASSWORD@MYLINKCREATE NEWTABLECOPY USING SELECT * FROM MYTABLE;

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Ch. 22: Oracle Net Oracle Net is Oracle’s networking software. Formerly called SQL*Net (7.x) and

Net8 (8.0.x and 8i). Oracle Net’s local configuration files are sqlnet.ora and tnsnames.ora. These

are located in ORACLE_HOME\network\admin. Example tnsnames.ora entries below.

LOCAL = (DESCRIPTION = (SOURCE_ROUTE = OFF) (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = TONYTEAL)(PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = ORACLE) ) )PHOENIX = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = phoenix.cs.iupui.edu)(PORT = 1521)) ) (CONNECT_DATA = (SID = OS80) ) )

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Ch. 23: Materialized Views

Materialized Views (formerly called Snapshots) pre-aggregate data, index the data, and therefore improve query performance. Oracle creates a table that holds the data that otherwise might be accessed from queries/views.

Materialized views are commonly used in reporting applications.

When you create a materialized view, you must specify:• The query the materialized view is based on.• The refresh schedule.• How the update is performed (update vs. complete refresh)• The key type (rowid vs. primary key)

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Ch. 37: Data Dictionary

Oracle’s Data Dictionary views stores all the information about what is stored in the database.

Three types of data dictionary views:• DBA_% views are only available to DBAs (granted DBA role) .• ALL_% views show all objects the user has privileges on.• USER_% views show only objects in your schema.

The Road Map views: DICT and DICT_COLUMNS• DICTIONARY (DICT) – describes other dictionary views• DICT_COLUMNS – describes columns of DICT views

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Ch. 37: Data Dictionary

Important Data Dictionary views:• USER_TABLES (TABS) – tables• USER_TAB_COLUMNS (COLS) – columns of tables• USER_VIEWS – views• USER_SYNONYMS (SYN) – synonyms• USER_SEQUENCES (SEQ) – sequences• USER_CONSTRAINTS – constraints• USER_CONS_COLUMNS – columns of the constraints• USER_INDEXES (IND) – indexes• USER_IND_COLUMNS – columns of indexes