Database, oracle Database

Database, oracle Database

Database
Character Set
UTF-8
GBK
Create Table Structure
Similar to Excel
Use lowercase letters whenever possible
Upper SQL Server letters
Prefix followed by underline
Data Type
Varchar
Bit
Commonly used to indicate gender
Int
Varchar
Datetime
PHP features. varchar is used for saving timestamp.
Text
Primary Key
Auto-increment Column
Foreign key
Foreign key relationship
Slave table
Master table
Three paradigms
First paradigm
Atomicity
Second paradigm
Each column is related to a primary key.
Third paradigm
Each column is directly related to the primary key.