MySQL Workbench建表时PK, NN, UQ, BIN, UN, ZF, AL的意思
[intrinsic column flags]
- PK: primary key (column is part of a pk)
- NN: not null (column is nullable)
- UQ: unique (column is part of a unique key)
- AI: auto increment (the column is auto incremented when rows are inserted)

[additional data type flags, depend on used data type]
- BIN: binary (if dt is a blob or similar, this indicates that is binary data, rather than text)
- UN: unsigned (for integer types, see docs: “10.2. Numeric Types”)
- ZF: zero fill (rather a display related flag, see docs: “10.2. Numeric Types”)