2. Software Oracle 12c is installed on departmental server machines.

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1 1. Introduction This note describes how to access the Oracle database management system on the departmental computer systems. Basic information on the use of SQL*Plus is included. Section 8 tells you how to get further information on this and the other Oracle products. 2. Software Oracle 12c is installed on departmental server machines. 3. Accessing Oracle Registration as an Oracle user gives access to the products referred to in Section 2. This note assumes that you are logged on to Oracle via a PC, such as those in 4th floor labs 403/404/405/ What You Can Do Access to Oracle is controlled through Oracle usernames and passwords. Systems Group will notify you of your username and initial password, and explain how to change your password. Students will normally be registered with privileges which enable you to: - SELECT data from your own tables and views, and other users data when SELECT access has been granted - INSERT, DELETE and UPDATE data in your own tables, and other users tables if the corresponding access has been granted - CREATE database tables, views and other objects - GRANT privileges on created objects to other users and REVOKE those privileges Students wishing to create tables are welcome to do so. Space in the database has been set aside for students data. 5. SQL*Plus SQL*Plus is an Oracle product which provides an interactive SQL interface to Oracle data. It supports not only the normal SQL statements such as SELECT, INSERT, CREATE TABLE, CREATE VIEW and so on, but also Oracle extensions providing extra capabilities such as for formatting reports, saving and retrieving SQL statements, and setting options affecting the SQL*Plus interface Entering, Executing Commands, Exiting To enter SQL*Plus, double click on the SQL*Plus icon: a Log On box appears which enables you to enter your Oracle username, password and the database ("Host String") which you wish to access, which is main. A message identifying the version of the software running will appear, followed by the normal SQL*Plus prompt: SQL> Any difficulty accessing SQL*Plus should be reported to Systems Group. Once successfully logged on to SQL*Plus, an SQL statement or one of the extra SQL*Plus commands may be executed. An SQL statement may be executed that continues over a number of lines, each completed by pressing <Enter>. A semicolon ; is used in SQL*Plus to indicate the end of an SQL statement and to execute it. This is SQL*Plus specific and not part of the SQL statement. For example, to retrieve details of all suppliers whose city is London, the following SQL statement may be typed over three lines:

2 - 2 - SQL> SELECT * 2 FROM SUPPLIER 3 WHERE CITY = LONDON ; As each additional line of the statement is entered, SQL*Plus automatically numbers that line. The terminating semicolon ; before the final <Enter> indicates to SQL*Plus that the SQL statement is complete and should be executed. SQL*Plus will display the data retrieved as a result of the SQL SELECT statement entered: S# SNAME STATUS CITY S1 SMITH S4 CLARK Any SQL statement may be used within SQL*Plus. For example, to create a table EMPLOYEE, the following SQL statement could be used: SQL> CREATE TABLE EMPLOYEE 2 (EMP_ID NUMBER(5) NOT NULL, 3 EMP_LAST_NAME VARCHAR2(20), 4 EMP_FIRST_NAME VARCHAR2(20)); SQL*Plus will respond with the message: Table created. To leave SQL*Plus, type EXIT The SQL*Plus Editor The most recent SQL statement entered is stored in a buffer. There it may be edited from within SQL*Plus. This enables typing mistakes to be corrected, or similar statements to be executed without complete retyping. As noted in Section below, a host operating system editor can be used for editing the most recent SQL statement. However, a line editor is also available which can be useful if executing from an environment, e.g. a remote login, which does not support a screen-based editor. Some useful line editing commands follow. Some of these rely on the notion of the current line in the buffer. This is indicated by a * when the buffer is listed. L List the contents of the SQL buffer L n List line n of the SQL buffer: the L can be omitted DEL Delete the current line I new Input text new after the current line C/old/new/ Change text in the current line, replacing old by new A new Append text new to the current line If the input command I is entered without any new text, SQL*Plus will prompt for lines of text to be input, until an empty line is entered (<Enter> by itself). Having edited the buffer, the SQL statement may be displayed and executed by typing SQL> RUN which may be shortened to just R. The / command executes the statement without displaying it. For example, assume that having entered the SQL SELECT statement seen in Section 5.1, you want to retrieve details of all suppliers whose city is Paris. The following SQL*Plus commands may be entered:

3 - 3 - SQL> L3 3* WHERE CITY = LONDON SQL> C/LONDON/PARIS/ 3* WHERE CITY = PARIS SQL> RUN 1 SELECT * 2 FROM SUPPLIER 3* WHERE CITY = PARIS S# SNAME STATUS CITY S2 JONES 10 PARIS S3 BLAKE 30 PARIS Note that the semicolon entered to terminate and execute the original SQL statement is not stored in the buffer. Also, the L, C and RUN commands do not have terminating semicolons since they are SQL*Plus commands rather than SQL statements to be executed Useful SQL*Plus Commands command can be used to execute SQL statements or SQL*Plus commands contained in a file. For example, if you have a file called H:\test.sql containing SQL statements or commands, they can be run by typing: command assumes the named file has suffix.sql by default. Any SQL statement or SQL*Plus command which may be entered interactively may be executed from a command file in this way SET SET options control various aspects of the SQL*Plus interface. For example: SET ECHO {OFF ON} SET FEEDBACK {OFF ON n} SET HEADING {OFF ON} SET PAGESIZE {n 0} SET PAUSE {OFF ON} Controls whether command file commands are displayed on execution. Controls whether number of rows retrieved is displayed. The n option ensures feedback only if more than n rows retrieved. Controls whether column headings are displayed. Controls number of lines n printed on each page with headings. The 0 option results in no pagination and no headings are displayed. Controls whether a page is displayed only after <Enter> is pressed. When using SQL*Plus on a PC, the Options menu also allows SQL*Plus environment parameters to be set.

4 EDIT It has been seen that the SQL*Plus line editor is very limited. The EDIT command (which may be shortened to ED) enables use of a host operating system editor to edit the buffer containing the most recent SQL statement. By default the Notepad editor is invoked on a PC. Hence SQL> EDIT will invoke Notepad to edit the most recent SQL statement in the buffer. (A file H:\afiedt.buf is created to hold this.) Within the file a / character denotes the end of the statement in the buffer. EDIT can also be used to edit a specified file as in: SQL> EDIT test In this case Notepad will be invoked to edit the file test.sql: as with command, a suffix.sql is assumed by default. When using SQL*Plus on a PC, the Edit menu also gives access to Notepad SPOOL You may wish to save the results of an SQL statement in a file, perhaps for subsequent printing. The SPOOL command results in any output displayed on the screen by SQL*Plus also being written to a named file. The SPOOL OFF command stops the writing of output to the file. For example, the following commands could be used to write the SELECT statement used in Section 5.1 and its output to a file H:\results.LST. SQL> SPOOL results SQL> SELECT * 2 FROM SUPPLIER 3 WHERE CITY = LONDON ; S# SNAME STATUS CITY S1 SMITH S4 CLARK SQL> SPOOL OFF Note that SPOOL creates a file with a.lst suffix by default. File H:\results.LST created will contain the lines displayed up to and including the SQL> SPOOL OFF line itself. However, be aware that the output to the file is buffered and will only be fully written to the named file after the SPOOL OFF command has itself been executed. When using SQL*Plus on a PC, the File menu also gives access to the SPOOL command DESCRIBE The DESCRIBE command displays information about the columns of a table. For example: SQL> DESCRIBE PROJECT Name Null? Type J# NOT NULL VARCHAR2(4) JNAME NOT NULL VARCHAR2(10) CITY NOT NULL VARCHAR2(15)

5 What Tables Do I Have Access To? The information about what tables are in the database is itself held in table form in the data dictionary (catalog). Amongst the tables in the data dictionary are: USER_TABLES - Description of the user s own tables ALL_TABLES - Description of tables the user has access to DICT - Description of all the tables in the data dictionary Use the DESCRIBE command to display information about the columns in these tables. 7. Can I Copy Tables For Use Elsewhere? If you are running Oracle elsewhere, you can "export" your own tables here to a file which you can then "import" into another Oracle system elsewhere. A (non-standard) form of CREATE TABLE makes it easy to create your own table containing the same rows as a table you have access to. For example, to create your own SUPPLIER table from the existing SUPPLIER table which you have access to, enter: SQL> CREATE TABLE SUPPLIER AS SELECT * FROM SUPPLIER; Having created your own table, you can then export it using an Oracle export utility such as Data Pump and then import it elsewhere using the same utility. See the next section for further information on documentation. Oracle does not provide utilities to export data to non-oracle systems. However, if you are running a DBMS elsewhere which enables row data to be loaded into tables from conventional files, SPOOL and SELECT could be used to create a file with the row data in whatever format is required for loading elsewhere. 8. Further Information Some further reading is suggested in this section. Since there are differences between the various versions of Oracle, including differences to the SQL commands supported, care must be taken to ensure any manual consulted refers to the same version of Oracle and its products as is being used. The Oracle documentation set can be accessed at: This includes links to the following on-line books: - SQL*Plus Quick Reference - SQL*Plus User s Guide and Reference - SQL Language Reference - Utilities

6 BIRKBECK COLLEGE Department of Computer Science and Information Systems Using Oracle 12c on PCs version 1.0 Table of Contents 1. Introduction Software Accessing Oracle What You Can Do SQL*Plus Entering, Executing Commands, Exiting The SQL*Plus Editor Useful SQL*Plus Commands SET EDIT SPOOL DESCRIBE What Tables Do I Have Access To? Can I Copy Tables For Use Elsewhere? Further Information... 5 Nigel Martin Oct 2013 Doc ref: /home/sg/doc/orapc.tn