[intrinsic column flags] (基本字段類型標識)
- PK: primary key (column is part of a pk) 主鍵
- NN: not null (column is nullable) 非空
- UQ: unique (column is part of a unique key) 唯一
- AI: auto increment (the column is auto incremented when rows are inserted) 自增
www.2cto.com
[additional data type flags, depend on used data type] 擴展數據類型標記
- BIN: binary (if dt is a blob or similar, this indicates that is binary data, rather than text) 二進制(比text更大的二進制數據)
- UN: unsigned (for integer types, see docs: “10.2. Numeric Types”) 整數
- ZF: zero fill (rather a display related flag, see docs: “10.2. Numeric Types”)值中最有意義的字節總為0，並且不保存。 www.2cto.com
ps: ZF個人理解指的是帶有小數占位符的數據相當於金額類型的數據。
