"SQL Server Learning Notes" (1)

Basic knowledge:

1. DDL (data definition language)
   

   Create object_name

   Alter object_name

   Drop object_name

2. DCL (Data Control Language)

   Grant (Authorization) eg:grant select on dbo. Tstudent to Public

   Deny (Deny) Eg:deny select,update on authors to Mary,john

   Revoke (cancel)

3. DML (Data Manipulation language)

   Select Insert Update Delete

4. @ Represents a local variable or parameter

5. #代表临时表或存储过程 (available only to the current user)

   # #代表全局临时表 (available to all users)

   Temporary tables are found in tempdb in the system database

6. Char is suitable for storing English, one byte occupies one byte;

   NCHAR suitable for storing Chinese, one character occupies 2 bytes
   

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"SQL Server Learning Notes" (1)