Shulou(Shulou.com)06/01 Report--

Brief introduction of parameters

When initializing the database with DMINIT, we have the following two character set-related parameters, UNICODE_FLAG and LENGTH_IN_CHAR.

UNICODE_FALG: this parameter represents the character set of all the data in the database, including the character set of the data dictionary. It is important to note that once the database is initialized, the character set cannot be modified. We can use select unicode to query the type of character set in the current database, where 0 represents gb18030,1 for UTF-8.

LENGTH_IN_CHAR: this parameter determines whether the length of VARCHAR type objects in the database is in characters. A value of 1 is set to the unit of characters, and the storage length value is enlarged according to the theoretical character length. A value of 0 results in the length of all objects of type VARCHAR in bytes.

Create table insert data Varchar (3)

Test 1. The LENGTH_IN_CHAR=0,UNICODE_FLAG=1 for initialization of Vardhar is as follows

Create table insert data Varchar (1)

Summary

Dameng sets the parameter LENGTH_IN_CHAR=0 (in varchar bytes) when initializing the instance. Utf- 8 occupies three bytes for one Chinese character, three bytes for all noon symbols and one byte for one English. Varchar is in bytes. A varchar equals a byte.

The LENGTH_IN_CHAR=1,UNICODE_FLAG=1 for initialization of Vardhar is as follows

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