Data Type Description
VARCHAR2( len) Can store up to len number of characters. Each character would occupy one byte. Maximum width is 4000 characters.VARCHAR(len) Same as VARCHAR2. But use VARCHAR2 as Oracle might change the usage of VARCHAR in future releases.
CHAR(len) Fixed length character data. If len is given then it can store up to len number of characters. Default width is 1. String is padded on the right with spaces until string is of len size. Maximum width is 2000.
NUMBER Can store numbers up to 40 digits plus decimal point and sign.
NUMBER (p ,s) P represents the maximum significant digits allowed. S is the number of digits on the right of the decimal point.
DATE Can store dates in the range 1-1-4712 B.C to 31-12-4712 AD.
LONG Variable length character values up to 2 gigabytes. Only one LONG column is allowed per table. You cannot use LONG datatype in functions, WHERE clause of SELECT, in indexing and subqueries.
RAW and LONG RAW Equivalent to VARCHAR2 and LONG respectively, but used for storing byte-oriented or binary data such as digital sound or graphics images.
CLOB, BLOB, NCLOB Used to store large character and binary objects. Each can accommodate up to 4 gigabytes. We will discuss more about it later in this book.
BFILE Stores a pointer to an external file. The content of the file resides in the file system of the operation system. Only the name of the file is stored in the column.
ROWID Stores a unique number that is used by Oracle to uniquely identify each row of the table.
NCHAR (size) Same as CHAR, but supports national language.
NVARCHAR2 (size) Same as VARCHAR2, but supports national language.
