The following table provides a more complete overview of the most important Oracle data types.
| Data type | Description |
|---|---|
| CHAR[(n)] | Character string with fixed length n (default 1) using the database characterset |
| VARCHAR|VARCHAR2(n) | Variable-length string; maximum n characters using the database characterset |
| NCHAR[(n)] | Character string with fixed length n (default 1) using the national characterset |
| NVARCHAR|NVARCHAR2(n) | Variable-length string; maximum n characters using the national characterset |
| DATE | Date (between 4712 BC and 9999 AD) |
| TIMESTAMP | Timestamp, with or without time zone information |
| INTERVAL | Date/time interval |
| BLOB | Unstructured binary data (Binary Large Object) |
| CLOB | Large text (Character Large Object) using the database characterset |
| NCLOB | Large text (Character Large Object) using the national characterset |
| RAW(n) | Binary data; maximum n bytes |
| NUMBER | Can store any number, maximum precision and scale 38 digits |
| NUMBER(n) | Integer; maximum n digits |
| NUMBER(n,m) | Total of n digits; maximum m digits right of the decimal point |
| BINARY_FLOAT | 32-bit floating-point number |
| BINARY_DOUBLE | 64-bit floating-point number |
If you insert values into a NUMBER(n,m) column and you exceed precision n, you get an error message.
If you exceed scale m, the oracle DBMS rounds the value.
Oracle DBMS supports many data type synonyms for portability.
For example, CHARACTER is identical to CHAR; DECIMAL(n,m) is identical to NUMBER(n,m); and NUMBER even has multiple synonyms, such as INTEGER, REAL, and SMALLINT.
Each Oracle data type has its own precision or length limits as shown in the following table.
| Data type | Limit |
|---|---|
| NUMBER | 38 digits |
| CHAR | 2000 bytes |
| VARCHAR | 4000 bytes |
| VARCHAR2 | 4000 bytes or 32,767 bytes2 |
| RAW | 2000 bytes or 32,767 bytes3 |
| BLOB | (4GB - 1) * (database block size) |
| CLOB | (4GB - 1) * (database block size) |