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1 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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2 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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3 Ch. 21: SQL*Loader Control File Examples Variable field control file Fixed field control file
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4 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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5 Ch. 22: Database Links Create Database Link syntax: CREATE DATABASE LINK MYLINK CONNECT TO ATEAL IDENTIFIED BY PASSWORD USING ‘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@MYLINK CREATE NEWTABLECOPY USING SELECT * FROM MYTABLE;
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6 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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7 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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8 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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9 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
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