Hi,,

I tink I found the answer to the daatypes' sizes in oracle:


Datatype Description Column Length and Default
CHAR (size)
Fixed-length character data of length size bytes
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 (one-byte or multibyte) before setting size.

VARCHAR2 (size)
Variable-length character data
Variable for each row, up to 4000 bytes per row: Consider the character set (one-byte or multibyte) before setting size: A maximum size must be specified.

NCHAR (size)
Fixed-length character data of length size characters or bytes, depending on the national character set
Fixed for every row in the table (with trailing blanks). Column size is the number of characters for a fixed-width national character set or the number of bytes for a varying-width national character set. Maximum size is determined by the number of bytes required to store one character, with an upper limit of 2000 bytes per row. Default is 1 character or 1 byte, depending on the character set.

NVARCHAR2 (size)
Variable-length character data of length size characters or bytes, depending on national character set: A maximum size must be specified
Variable for each row. Column size is the number of characters for a fixed-width national character set or the number of bytes for a varying-width national character set. Maximum size is determined by the number of bytes required to store one character, with an upper limit of 4000 bytes per row. Default is 1 character or 1 byte, depending on the character set.

CLOB
Single-byte character data
Up to 2^32 - 1 bytes, or 4 gigabytes.

NCLOB
Single-byte or fixed-length multibyte 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 2^31 - 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.E. to Dec. 31, 4712 C.E.
Fixed at 7 bytes for each row in the table. Default format is a string (such as DD-MON-YY) specified by NLS_DATE_FORMAT parameter.

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
Binary data representing row addresses
Fixed at 10 bytes (extended ROWID) or 6 bytes (restricted ROWID) for each row in the table.

MLSLABEL
Trusted Oracle datatype
See the Trusted Oracle documentation.