SQL and SQL*Plus Interaction

SQL*PlusSQL*Plus

SQL StatementsSQL StatementsBufferBuffer

SQL StatementsSQL Statements

Server

Query ResultsSQL*PlusSQL*Plus CommandsCommands

Formatted ReportFormatted Report

SQL Statements Vs SQL*Plus Commands

SQLSQLstatementsstatements

SQL

• A command language used for communication with the Oracle Server to access data

• When a SQL statement is entered, it is stored in a part of memory called the SQL buffer and remains there until a new statement is entered

SQL*Plus

• An environment

• SQL*Plus is an Oracle tool that recognizes and submits SQL statements to Oracle Server for execution

• Provides a line editor for modifying SQL statements

• Is entered one line at a time, not stored in the SQL buffer

SQLSQLbufferbuffer

SQL*PlusSQL*Pluscommandscommands

SQL*PlusSQL*Plusbufferbuffer

SQL Statements Vs SQL*Plus Commands SQL

• It is based on ANSI standard SQL

• Keyword can’t be abbreviated

• Statements manipulate data and table definitions in the database

• It does not have a continuation character

• Uses a termination character to execute command immediately

• Uses functions to perform some formatting

SQL*Plus

• Oracle proprietary interface for executing SQL statements

• Keywords can be abbreviated

• Commands do not allow manipulation of values in the database

• Has a dash(-) as a continuation character if the command is longer than one line

• Does not require a termination characters. Commands are executed immediately

• Uses commands to format data

• Log in to SQL*Plus.• Describe the table structure.• Edit your SQL statement.• Execute SQL statements from SQL*Plus

to:– Retrieve, modify, add, and remove data from the

database

• Format, perform calculations on, store, and print query results in the form of reports

• Save SQL statements to files– Create script files to store SQL statements for

repetitive use in the future

• Append SQL statements to files.• Execute saved files.• Load commands from file to buffer to

edit.

Overview of SQL*Plus

Logging In to SQL*Plus

Displaying Table StructureUse the SQL*Plus Use the SQL*Plus DESCRIBEDESCRIBE command to command to display the structure of a table.display the structure of a table.

DESC[RIBE] tablenameDESC[RIBE] tablename

SQL> DESCRIBE deptSQL> DESCRIBE dept

Name Null? Type----------------- -------- ------------DEPTNO NOT NULL NUMBER(2)DNAME VARCHAR2(14)LOC VARCHAR2(13)

Name Null? Type----------------- -------- ------------DEPTNO NOT NULL NUMBER(2)DNAME VARCHAR2(14)LOC VARCHAR2(13)

Example:

The result of the command is to see the column The result of the command is to see the column names, data types, as well as whether a column names, data types, as well as whether a column must contain data.must contain data.

Displaying Table StructureSQL> DESCRIBE deptSQL> DESCRIBE dept

Name Null? Type----------------- -------- ------------DEPTNO NOT NULL NUMBER(2)DNAME VARCHAR2(14)LOC VARCHAR2(13)

Name Null? Type----------------- -------- ------------DEPTNO NOT NULL NUMBER(2)DNAME VARCHAR2(14)LOC VARCHAR2(13)

Data TypeData Type DescriptionDescriptionNUMBER(p, s)NUMBER(p, s) Number value having a maximum number of digits Number value having a maximum number of digits pp, the , the

number of digits to the right of the decimal point number of digits to the right of the decimal point ss

VARCHAR2(S)VARCHAR2(S) Variable-length character value of maximum size Variable-length character value of maximum size ss

DATE Date and time value between January 1, 4712 BC and Date and time value between January 1, 4712 BC and December 31, 9999 ADDecember 31, 9999 AD

CHAR(S) Fixed-length character value of size Fixed-length character value of size ss

SQL*Plus Editing Commands

• A[PPEND] text

• C[HANGE] / old / new

• C[HANGE] / text /

• CL[EAR] BUFF[ER]

• DEL

• DEL n

• DEL m n

• I[NPUT]

• I[NPUT] text

• L[IST]

• L[IST] n

• L[IST] m n

• R[UN]

• n

• n text

• 0 text

SQL*Plus Editing Commands

• A[PPEND] text• Adds text to the end of the current line

• C[HANGE] / old / new• Changes old text to new text in the current line

• C[HANGE] / text /• Deletes text from the current line

• CL[EAR] BUFF[ER]• Deletes all lines from the SQL buffer

• DEL• Deletes current line

• DEL n• DEL m n

SQL*Plus Editing Commands• I[NPUT]

• Inserts an indefinite number of lines• I[NPUT] text

• Inserts a line consisting of text• L[IST]

• Lists all lines in the SQL buffer• L[IST] n

• Lists one line (specified by n)• L[IST] m n

• Lists a range of lines (from m to n)• R[UN]

• Displays and runs the current SQL statement in the buffer• n

• Specifies the line to make the current line• n text

• Replaces line n with text• 0 text

• Inserts a line before line 1

SQL*Plus Editing Commands

SELECT FEATUER, PAGEFROM NEWSPAPERWHERE SECTION = ‘F’;

ORACLE responds:ERROR at line 1: ORA-0704: invalid column name

TWO Solutions:

1. Retype the whole query2. Use command to correct spelling of FEATUER

SQL*Plus Editing CommandsSELECT FEATUER, PAGEFROM NEWSPAPERWHERE SECTION = ‘F’;

Solution:Name of command: list

SQL>list

Result:1 SELECT FEATUER, PAGE2 FROM NEWSPAPER3* WHERE SECTION = ‘F’

SQL*Plus shows all three lines, and numbered them. It also places * next to line 3, which means it is the line your editing commands are able to affect. But we want to change line 1, so type:

SQL*Plus Editing CommandsSELECT FEATUER, PAGEFROM NEWSPAPERWHERE SECTION = ‘F’;

Solution:Name of command: list 1

SQL>list 1

Result:1* SELECT FEATUER, PAGE

Line 1 is displayed and is now the current line. We change it by typing:

CHANGE /FEATUER/FEATURE

Result:1* SELECT FEATURE, PAGE

SQL*Plus Editing Commands

Check the whole query again with:

list

1 SELECT FEATUER, PAGE2 FROM NEWSPAPER3* WHERE SECTION = ‘F’;

Place / at SQL> prompt and query will be executed.

SQL*Plus Editing CommandsCheck the whole query again with:

list

1 SELECT FEATUER, PAGE2 FROM NEWSPAPER3* WHERE SECTION = ‘F’;

To delete the current line:

del

Check the whole query again with:

list

1 SELECT FEATUER, PAGE2* FROM NEWSPAPER

SQL*Plus Editing CommandsTo clear the whole select statement completely, type:

clear buffer

If you like to append something to the current line, type:

SQL>list 1

1* SELECT FEATUER, PAGE

SQL>append “where it is”

1* SELECT FEATUER, PAGE “where it is”

append places its text right up against the end of the current line, with no spaces in between. To put a space in, type two spaces between the word append and the text.

SQL*Plus Editing CommandsWe may also input a whole new line after the current line:

SQL> list

1 SELECT FEATUER, PAGE2* FROM NEWSPAPER

SQL>input where section = ‘A’

SQL> list

1 SELECT FEATUER, PAGE2 FROM NEWSPAPER3* where section = ‘A’

Run it SQL> /

SQL*Plus File Commands

• SAVE filename

• GET filename

• START filename

• @ filename

• EDIT filename

• SPOOL filename

SQL*Plus File Commands• SAV[E] filename[.ext] [ REPLACE | APP[END] ]

• Saves current contents of SQL buffer to a file. Use APPEND to add to an existing file; use REPLACE to overwrite an existing file. The default extension is .sql.

• GET filename[.ext]• Writes the contents of a previously saved file to the SQL buffer. The default

extension is .sql.• START filename[.ext]

• Runs a previously saved command file.• @ filename

• Runs a previously saved command file (same as START).• ED[IT]

• Invokes the editor and saves the buffer contents to a file named afiedt.buf• ED[IT] filename[.ext]

• Invokes editor to edit contents of a saved file• SPO[OL] [ filename[.ext] | OFF OUT ]

• Stores query results in a file. OFF closes the spool file. OUT closes the spool file and sends the file results to the system printer.

• EXIT• Leaves SQL*Plus.

SQL*Plus File Commands

We can save the SQL created so far:

SQL> save abc.sql

SQL*PLUS responds:

Wrote file abc.sql

Now, the SQL statement is in file abc.sql.