First, install the extension
pip install flask-sqlalchemy
pip install flask-mysqldb
二、SQLAlchemy
SQLAlchemy common field type
| Type Name | Type in python | Explanation |
|---|---|---|
| Integer | int | Plain integers, typically 32 |
| SmallInteger | int | A small range of integers, typically 16 |
| BigInteger | int or long | Does not limit the integer precision |
| Float | float | Float |
| Numeric | decimal.Decimal | Plain integers, typically 32 |
| String | str | Variable-length strings |
| Text | str | Variable-length string, the string is not limited to or longer length optimized |
| Unicode | unicode | Variable-length Unicode string |
| UnicodeText | unicode | Variable-length Unicode strings, strings of length longer or not optimized |
| Boolean | bool | Boolean value |
| Date | datetime.date | time |
| Time | datetime.datetime | Date and Time |
| LargeBinary | str | binary file |
Commonly used SQLAlchemy Column Options
| Option name | Explanation |
|---|---|
| primary_key | If the primary key True, the representative of the table |
| unique | If True, the representative of this column does not allow duplicate values |
| index | If you create an index for this column to True, improve query efficiency |
| nullable | If True, it allows nulls, If False, does not allow nulls |
| default | The default value for this column definition |
Commonly used SQLAlchemy relationship options
| Option name | Explanation |
|---|---|
| backref | Adding another model referenced in the reverse relations |
| primary join | Explicitly specify the conditions of use of the coupling between the two models |
| uselist | If False, do not use the list, and use a scalar value |
| order_by | Specify the relationship recorded in Sort |
| secondary | Specified ordering many-recorded |
| secondary join | When not in SQLAlchemy discretion, specify two join condition in many relationship |