Oracle in a Nutshell

Parameters

variable_name

Name you want to give the variable. If you stop here and don’t supply a datatype, SQL*Plus displays the datatype for the variable that you have named.

data_type

Datatype of the variable. The following datatypes are allowed:

NUMBER

Results in a floating-point number and is the same as a NUMBER variable in PL/SQL or a NUMBER column in a table. Unlike PL/SQL, SQL*Plus does not let you specify a length or a precision, so a declaration like NUMBER (9,2) is not allowed.

CHAR [( length [CHAR | BYTE])]

Results in a fixed-length character string. The length is optional. If it is omitted, you get a one-byte string.

NCHAR [( length )]

Results in a fixed-length character string in the national character set. The length is optional. If it is omitted, you get a one-character string.

VARCHAR2 ( length [CHAR | BYTE])

Results in a variable-length character string.

NVARCHAR2 ( length )

Results in a variable-length character string using the national language character set.

CLOB

Results in a character large object variable.

NCLOB

Results in a character large object variable using the national language character set.

REFCURSOR

Gives you a cursor variable you can use to return the results of a SQL query from PL/SQL to SQL*Plus.