Oracle: Datatypes


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Datatype Description
Char A fixed length character field, up to 2,000 bytes in length.
Nchar A fixed length field for multibyte character sets. Max size is 2000 characters or 2000 bytes, depending on the characterset.
varchar2 A variable lenght character field, up to 4000 characters in length.
nvarchar2 A variable length fiedl for multibyte character sets. Max size is 4000 characters or 4000 bytes depending on the characterset.
date A fixed lenght 7 byte field used to store dates. Displayed date format can be overridden with the NLS_DATE_FORMAT parameter.
number A variable length number column. Provides facility for Precision and scale number(9,2) specifies a floating point number nine digits long, two of which are to the right of the decimal point.
long A variable length field up to 2 gigs in length.
raw A variable length field used for binary data up to 2,000 bytes in length.
long raw A variable length field used for binary data up to 2 gigs in length.
mlslabel For trusted Oracle only; this data type uses between 2 and 5 bytes per row.
blob Binary large object - up to four gigs long.
clob Character large object - up to four gigs long
nclob Clob datatype for multibyte character sets up to four gigs long.
bfile External binary file; size limit is os dependent.
rowid Binary data representing a rowid. Value will be 1 bytes for Oracle 8 rowid values; 6 bytes for restricted rowid format used in Oracle 7.
urowid Binary data used for data addressing up to 4,000 bytes in length.

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