Kingbasees plug-in DBMS of Jincang database_ RANDOM

Catalog

1. DBMS_RANDOM

2. INITIALIZE Procedure

3. NORMAL Function

4. RANDOM Function

5. SEED Procedure

6. STRING Function

7. TERMINATE Procedure

8. VALUE Function

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1. DBMS_RANDOM

1.1. DBMS_RANDOM Introduce
KingbaseES Provides DBMS_RANDOM Random data generation function defined under the system package .DBMS_RANDOM The system package provides a random number or character generator .
You need to create extension dbms_random, When you don't need to drop extension dbms_random that will do .
The following table lists them DBMS_RANDOM System packages and a brief description of them .
surface 1 DBMS_RANDOM Package subroutines and functions

Subroutines / function	describe
INITIALIZE	Use a seed value to initialize the package
NORMAL Function	Produce a standard normal distribution function
RANDOM Function	Generate a random integer
SEED Procedure	Reset random number seed
STRING Function	Generate a random string
TERMINATE Procedure	Provides syntactic compatibility without performing any operations
VALUE Function	Generates a random number in a specified range

2. INITIALIZE Procedure

Use a seed value to initialize DBMS_RANDOM package , By default ,DBMS_RANDOM The package is based on the user 、 Time 、 Session to initialize .Initialize This function is obsolete , Although currently supported , However, this initialization method is reserved for historical reasons and compatibility .
Grammar format ：

DBMS_RANDOM.INITIALIZE(init INTEGER);

Parameter description ：

surface 2 initialize Parameters

Parameters	describe
init	Random number seed value

Return value description ：
VOID
Example ：

CALL dbms_random.initialize(8);

3. NORMAL Function

Produce a standard normal distribution function , The standard deviation of this normal distribution is 1, The expected value is 0.
Grammar format ：

DBMS_RANDOM.NORMAL();

Parameter description ：
No arguments
Return value description ：DOUBLE
Example ：

SELECT dbms_random.normal();

4. RANDOM Function

Generate a random integer , This function is out of date , Although it still supports , But it should not be used , Keep this function for compatibility .
Grammar format ：

DBMS_RANDOM.RANDOM();

Parameter description ：
No arguments
Return value description ：
NTEGER
Example ：

CALL dbms_random.random();

5. SEED Procedure

Reset seed , Be similar to initialize function ,initialize Functions have been eliminated . seed Function supports both numeric and character values as seed values , and initialize Only numerical values are supported .
Grammar format ：

DBMS_RANDOM.SEED(i INTEGER);
DBMS_RANDOM.SEED(t TEXT);

Parameter description ：

surface 3 seed Parameters

Parameters	describe
i	Random number seed value
t	Random number symbol seed value

Return value description ：

surface 4 seed Return value

function	type
SEED(i INTEGER)	VOID
SEED(t TEXT)	VOID

Example ：

CALL dbms_random.seed(8);
CALL dbms_random.seed('test');

6. STRING Function

Get a random string , The first parameter is the format of the string , The second parameter is the length of the string . Maximum length 5000, If the parameter exceeds 5000 Will automatically use 5000 Handle .
Grammar format ：

DBMS_RANDOM.STRING(type TEXT,len INTEGER);

Parameter description ：

surface 5  string Parameters

 

Parameters	describe
type	The type of string generated
len	The length of the resulting string

surface 6  type The corresponding meaning of the parameter

'x','X'	Returns a string of uppercase letters and numbers
'p','P'	Returns a string of any printable character

Return value description ：
TEXT
Example ：

SELECT dbms_random.string('U',5);
SELECT dbms_random.string('P',2);
SELECT dbms_random.string('x',4);
SELECT dbms_random.string('a',2);
SELECT dbms_random.string('l',3);

7. TERMINATE Procedure

The original function is to finish using dbms_random Execute this function when package , But now this function does nothing , Reserved for syntax compatibility .
Grammar format ：

DBMS_RANDOM.TERMINATE();

Parameter description ：
No arguments
Return value description ：
VOID
Example ：

CALL dbms_random.terminate();

8. VALUE Function

The first way to use no parameters is to get a value greater than or equal to 0 And less than 1 The random number , Accuracy of 16 Decimal place .
In the second way, you can specify the minimum and maximum values , The range of the return value is greater than or equal to low, Less than high, The accuracy is the same as 16 Decimal place .
Grammar format ：

DBMS_RANDOM.VALUE();
DBMS_RANDOM.VALUE(low INTEGER,high INTEGER);

Parameter description ：

surface 7 value Parameters

Parameters	describe
low	The minimum value of the generated random number
high	The maximum value of the generated random number

 

Return value description ：

surface 8 value Return value

function	type
VALUE()	VOID
VALUE(low INTEGER,high INTEGER)	VOID

Example ：

SELECT dbms_random.value();
SELECT dbms_random.value(10,15);