Gbase8s database restrictions on set collection

although SET COLLATION Enables you to dynamically change the comparison order of the database server within the session , But you should understand that

SET COLLATION Several limitations of the scope in which statements can work .

Only the comparison performed by the database server is affected . Client processes that sort data are not affected SET COLLATION shadow

ring .

Only the current session is affected . Other conversations are not affected by your SET COLLATION The direct impact of the statement , But the database server

Servers will use their creation time comparison order to set any database objects , These database objects are what you have successfully

Running smoothly SET COLLATION Those created later .

Changes to the collation order do not change the code set . The database server usually uses DB_LOCALE Specified code

Set .

Only in locale specific order NCHAR and NVARCHAR Value to sort .

Handle characters from different code sets

because SET COLLATION Only change the comparison order , Not the current locale or code set , Therefore, you should not use this

Statement to insert character data from different locales into the same database . If the database needs to store data from two or

Multilingual characters , These languages inherently require different code sets or code pages , Then you must use support instead Unicode

Language environment of . about GBase 8s ESQL/C application , And for using GBase 8s GLS Other client applications of the Library ,

Its locale supports UTF-8 The character encoded database can store codes corresponding to different character sets from multiple natural languages

Character of dot , But only if all the following conditions are met ：

When the database server instance starts , Set up GL_USEGLU The environment variable is 1.

When creating a database , Set up DB_LOCALE The environment variable is valid Unicode Language environment .

Set up CLIENT_LOCALE The environment variable is... Of the database server DB_LOCALE Set the supported valid

Unicode Language environment .

about GBase 8s To use “Unicode International components of ”（ICU）4.8.1 Library to support up to 6.0 Of Unicode Edition

Ben , Before starting the server , In the server environment GL_USEGLU The environment variable is set to a value 1（ One ）. Making

use UTF-8 Character encoded database , This setting initializes enabling Unicode Control and SQL Those conversion rules of operation ,

Include Chinese GB18030-2000 Code set . This conversion is only applicable to GL_USEGLU=1 Created data

library .

Be careful ： However ,GL_USEGLU Environment variables are important to JDBC The client application does not work , Include GBase 8s JSON Compatibility

Line protocol listener Those applications . To be in Unicode Correctly support JDBC application , Not on the client

Or in the server environment GL_USEGLU Set to 1 The requirements of