(c) PL/SQL data type

PL/SQL variables, constants, and parameters must have a valid data type, specifying a valid range of storage formats, constraints, and values.

category	Description
Scalar	Single value does not have an internal component, such as number, DATE, or BOOLEAN
Large Object (LOB)	Store large objects that point to other data items such as text, graphics images, video clips, and sounds
Composite	A data item with an internal component that can be accessed separately. For example, collections and records
Reference	Point to other data items

First, scalar
1.pl/sql scalar data types and subtypes

Data Type	Description
Digital	The numeric value of the arithmetic operation performed on it
Character	An alphanumeric string value that represents a single character or character
Boolean	Logical value of the logical operation on which to execute
Date Time	Date and time

2.pl/sql numeric data types and subtypes

Data Type	Description
Pls_integer	Signed integers in the range 2,147,483,647 to 2147483648, denoted by 32 bits
Binary_integer	A signed integer in the range of 2,147,483,647 to 2147483648, represented by 32 bits
Binary_float	Floating-point number in single-precision IEEE 754 format
Binary_double	Double-precision floating-point number in IEEE 754 format
Number (PREC, scale)	Fixed-point or floating-point number in the range 1E-130 to (but not including) the absolute value 1.0E126. The number variable can also represent 0
DEC (PREC, scale)	ANSI specific fixed-point type uses 38-bit decimal maximum precision
DECIMAL (PREC, scale)	IBM-specific fixed point type with 38 decimal places maximum precision
NUMERIC (pre, Secale)	Floating-point types have a maximum precision of 38 decimal places.
DOUBLE PRECISION	With 126 binary digits maximum precision ANSI-specific float (approx. 38 decimal digits)
FLOAT	With 126 binary digits (approximately 38 decimal digits) Maximum precision ANSI and IBM-specific floating-point type
Int	With 38 decimal places maximum precision ANSI specific integer type
INTEGER	38-bit decimal maximum precision specific integer type for ANSI and IBM
SMALLINT	38-bit decimal maximum precision specific integer type for ANSI and IBM
REAL	Maximum precision floating point with 63-bit binary digits (approximately 18 decimal places)

3.pl/sql character data types and subtypes

data type	description
CHAR	a fixed-length string with a maximum size of 32,767 bytes
VARCHAR2	has a maximum size of 32,767 bytes variable length string
RAW	The maximum size of 32,767 bytes of a variable-length binary or byte string, rather than PL/SQL interpretation
NCHAR	A fixed-length country string with a maximum size of 32,767 bytes
NVARCHAR2	has a maximum size of 32,767 bytes variable length country string
Long	has a 32,760-byte maximum size variable length string
LONG RAW	The maximum size of a variable-length binary or byte string of 32,760 bytes, rather than PL/SQL interpretation
rowid	physical row identifier, one row in the address of a normal table
urowid	physical Universal Row Identifier (physical, logical, or foreign row identifier)

4.pl/sql Boolean data type
A logical value stored using a Boolean data type in a logical operation. The logical values are Boolean values that are true and false, and NULL values.
However, SQL does not have a data type equal to Boolean. Therefore, the Boolean value cannot be used for:
. SQL statements
. Built-in SQL functions (such as TO_CHAR)
. Calling the PL/SQL function from an SQL statement

5.pl/sql date Time and interval type

Field name	valid datetime value	valid interval value
Year	-4712 to 9999 (excluding year 0)	Any non-0 integer
MONTH	12	0 to 11
Day	31 (subject to the values of the year and month, as set by the locale of the calendar)	Any non-0 integer
HOUR	XX to 23	0 to 23
MINUTE	XX to 59	0 to 59
SECOND	XX to 59.9 (n), where 9 (n) is the time fractional seconds precision	0 to 59.9 (N), where 9 (n) is the interval fractional seconds precision
Timezone_hour	-12 to 14 (range accommodates daylight saving time changes)	Not applicable
Timezone_minute	XX to 59	Not applicable
Timezone_region	Find V$timezone_names in Dynamic performance view	Not applicable
Timezone_abbr	Find V$timezone_names in Dynamic performance view	Not applicable

Ii. large Object (LOB)
Large object (LOB) data types are large to data items such as text, graphic images, video clips, and sound waveforms. LOB data types allow for efficient, random, segmented access to these data. The following are the predefined PL/SQL LOB data types:

Data Type	Description	size
BFILE	System files for storing large binary objects outside the operational database	dependent on system, cannot exceed 4,000 gigabytes (GB)
Blob	Used to store large binary objects in the database	8 to 128 terabytes (TB) of
Clob	Used to store characters in large chunks of data in a database	8-128 TB
NCLOB	Used to store large chunks of nchar data in a database	8-128 TB

(c) PL/SQL data type