MySQL Learning (iii): Primary knowledge Data Sheet

Tag: the IMG number automatically does not have a data table looking for alt ima. com

Open the database:

• Use db_name: Open the database.

  To create a data table:

View Data Sheet:

To view the data table structure:

Simple insertion and lookup of data:

• Insert: Insert [into] tbl_name [(col_name)] VALUES (Val1,val2,...);
• Find: SELECT expression from Tbl_name

NULL and non-null:

• NULL and non-null are not specified when the table is established, and can be null by default.
• When you create a table, you can add some corresponding properties to the column name-data type

Auto Number:

Primary key: Primary key non-null

Unique constraint: Uniue KEY can be empty

Default constraints:

Example:

• Record Lookup:
  

• View the data table structure

• Create:
  

MySQL Learning (iii): Primary knowledge Data Sheet