[Q] How to view the database character set [A] Database server character set Select * from NLS_DATABASE_PARAMETERS, which is from PROPS $, which is a character set that represents the database. Client character set environment Select * from nls_instance_parameters, comes from V $ parameter, indicating the settings of the client's character set, may be parameter files, environment variables, or registry session character set environment Select * from NLS_Session_Parameters, come from V $ NLS_Parameters, indicating that the session is your own setting, which may be the environment variable of the session or the ALTER session complete, if the session does not have a special setting, will be consistent with NLS_INSTANCE_PARAMETERS. The client's character set requires the same as the server to correctly display the non-ASCII characters of the database. If multiple settings exist, the Alter Session> Environment Variable> Registry> Parameter file character set is consistent, but the language settings can be different, and the language settings are recommended in English. If the character set is ZHS16GBK, the nls_lang can be American_america.zHS16GBK.
[Q] How to modify the character set [A] 8i or more version can modify the character set through Alter Database, but it is only limited to subset to superchard, and it is not recommended to modify the PROPS $ table, which will cause serious errors. Startup Nomount; Alter System Enable Restricted Session; ALTER System Set Job_Queue_Process = 0; ALTER DATABASE OPEN; ALTER DATABASE CHARACTER SET ZHS16GBK;
