Each column value and constant in a SQL statement has a data type, which is associated with a specific storage format, constraints, and a valid range of values. When you create a table, you must specify a datatype for each of its columns.
Oracle provides the following categories of built-in datatypes:
- Overview of Character Datatypes
- Overview of Numeric Datatypes
- Overview of DATE Datatype
- Overview of LOB Datatypes
- Overview of RAW and LONG RAW Datatypes
- Overview of ROWID and UROWID Datatypes
The following sections that describe each of the built-in datatypes in more detail.
Overview of Character Datatypes :
The character datatypes store character (alphanumeric) data in strings, with byte values corresponding to the character encoding scheme, generally called a character set or code page.
The database's character set is established when you create the database. Examples of character sets are 7-bit ASCII (American Standard Code for Information Interchange), EBCDIC (Extended Binary Coded Decimal Interchange Code), Code Page 500, Japan Extended UNIX, and Unicode UTF-8. Oracle supports both single-byte and multibyte encoding schemes.
This section includes the following topics:
- CHAR Datatype
- VARCHAR2 and VARCHAR Datatypes
- Length Semantics for Character Datatypes
- NCHAR and NVARCHAR2 Datatypes
- Use of Unicode Data in Oracle Database
- LOB Character Datatypes
- LONG Datatype
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