Learning materials
www.bilibili.com/video/BV1NJ…
The column type of the database
Integer: int
Floating-point numbers in the form of decimal strings, which solve precision loss problems
Char The character string contains 0 to 255 characters of fixed size
Vachar The variable value ranges from 0 to 65535
Text Text string 2 to the 16th power -1
Date Date format
Time Time format
Datetime Indicates the common time format
Timestamp timestamp
During the year
Field properties of the database
Unsigned: an Unsigned integer. The column cannot be negative
Zerofill: 0 fill, insufficient bits, filled with 0
Increment: Must be an integer and is generally used for the primary key of a table
Non-empty: An error will be reported if the value is not entered
Type of data table
— | MYISAM before (5.5) | INNODB |
---|---|---|
Transaction support | Does not support | support |
Row lock | Does not support | support |
Outside the building constraints | Does not support | support |
The full text indexing | support | Does not support |
The size of the tablespace | smaller | Larger, about twice as large |
Conclusion:
- MYISAM saves space and is faster
- INNODB has high security, transaction processing, multi-table multi-user operation