MySQL建表時，基本字段的含義

[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) 惟一

• AI: auto increment (the column is auto incremented when rows are inserted) 自增

[additional data type flags, depend on used data type] 擴展數據類型標記

• BIN: Is binary column (if data is a blob or similar, this indicates that is binary data, rather than text) 存放二進制數據的列

• UN: unsigned (for integer types, see docs: 「10.2. Numeric Types」) 無符號整數

• ZF: Fill up values for that column with 0's if it is numeric (rather a display related flag, see docs: 「10.2. Numeric Types」)填充0位（例如指定3位小數，整數18就會變成18.000）