Data Type	Description	Column Length and Default
CHAR (size [BYTE | CHAR])	Fixed-length character data of length size bytes or characters.	Fixed for every row in the table (with trailing blanks); maximum size is 2000 bytes per row, default size is 1 byte per row. Consider the character set (single-byte or multi-byte) before setting size.
VARCHAR2 (size [BYTE | CHAR])	Variable-length character data, with maximum length size bytes or characters.	Variable for each row, up to 4000 bytes per row. Consider the character set (single-byte or multi-byte) before setting size. A maximum size must be specified.
NCHAR (size)	Fixed-length Unicode character data of length size characters.	Fixed for every row in the table (with trailing blanks). Column size is the number of characters. (The number of bytes is 2 times this number for the AL16UTF16 encoding and 3 times this number for the UTF8 encoding.) The upper limit is 2000 bytes per row. Default is 1 character.
NVARCHAR2 (size)	Variable-length Unicode character data of length size characters. A maximum size must be specified.	Variable for each row. Column size is the number of characters. (The number of bytes may be up to 2 times this number for a the AL16UTF16 encoding and 3 times this number for the UTF8 encoding.) The upper limit is 4000 bytes per row. Default is 1 character.
CLOB	Single-byte character data	Up to 2^32 - 1 bytes, or 4 gigabytes.
NCLOB	Unicode national character set (NCHAR) data.	Up to 2^32 - 1 bytes, or 4 gigabytes.
LONG	Variable-length character data.	Variable for each row in the table, up to 2^32 - 1 bytes, or 2 gigabytes, per row. Provided for backward compatibility.
NUMBER (p, s)	Variable-length numeric data. Maximum precision p and/or scale s is 38.	Variable for each row. The maximum space required for a given column is 21 bytes per row.
DATE	Fixed-length date and time data, ranging from Jan. 1, 4712 B.C.to Dec. 31, 9999 A.D..	Fixed at 7 bytes for each row in the table. Default format is a string (such as DD-MON-RR) specified by the NLS_DATE_FORMAT parameter.
TIMESTAMP (frac_ seconds_precision)	A value representing a date and time, including fractional seconds. (The exact resolution depends on the operating system clock.) The precision value specifies the number of digits in the fractional second part of the SECOND date field. The precision can be from 0 to 9, and defaults to 6	Varies from 7 to 11 bytes, depending on the precision. The default is determined by the NLS_TIMESTAMP_FORMAT initialization parameter.
TIMESTAMP (frac_ seconds_precision) WITH TIME ZONE	A value representing a date and time, plus an associated time zone setting. The time zone can be an offset from UTC, such as '-5:0', or a region name, such as 'US/Pacific'.	Fixed at 13 bytes. The default is determined by the NLS_TIMESTAMP_TZ_FORMAT initialization parameter.
TIMESTAMP (frac_ seconds_precision) WITH LOCAL TIME ZONE	Similar to TIMESTAMP WITH TIME ZONE, except that the data is normalized to the database time zone when stored, and adjusted to match the client's time zone when retrieved.	Varies from 7 to 11 bytes, depending on the precision. The default is determined by the NLS_TIMESTAMP_FORMAT initialization parameter.
INTERVAL YEAR (year_precision) TO MONTH	A period of time, represented as years and months. The precision value specifies the number of digits in the YEAR field of the date. The precision can be from 0 to 9, and defaults to 2 for years.	Fixed at 5 bytes.
INTERVAL DAY (day_precision) TO SECOND (frac_ seconds_precision)	A period of time, represented as days, hours, minutes, and seconds. The precision values specify the number of digits in the DAY and the fractional SECOND fields of the date. The precision can be from 0 to 9, and defaults to 2 for days and 6 for seconds.	Fixed at 11 bytes.
BLOB	Unstructured binary data	Up to 2^32 - 1 bytes, or 4 gigabytes.
BFILE	Binary data stored in an external file	Up to 2^32 - 1 bytes, or 4 gigabytes.
RAW (size)	Variable-length raw binary data	Variable for each row in the table, up to 2000 bytes per row. A maximum size must be specified. Provided for backward compatibility.
LONG RAW	Variable-length raw binary data	Variable for each row in the table, up to 2^31 - 1 bytes, or 2 gigabytes, per row. Provided for backward compatibility.
ROWID	Base 64 string representing the unique address of a row in its table. This data type is primarily for values returned by the ROWID pseudo-column.	Fixed at 10 bytes (extended ROWID) or 6 bytes (restricted ROWID) for each row in the table.
UROWID [(size)]	Base 64 string representing the logical address of a row of an index-organized table. The optional size is the size of a column of type UROWID.	The maximum size and default is 4000 bytes.