from fastapi import Depends, FastAPI, HTTPException

from . import crud, database, models, schemas
from .database import db_state_default

database.db.connect()
database.db.create_tables([models.User, models.Item])
database.db.close()

app = FastAPI()

sleep_time = 10


async def reset_db_state():
    database.db._state._state.set(db_state_default.copy())
    database.db._state.reset()

pkg database/sql, method (*NullByte) Scan(interface{}) error
pkg database/sql, method (*NullInt16) Scan(interface{}) error
pkg database/sql, method (NullByte) Value() (driver.Value, error)
pkg database/sql, method (NullInt16) Value() (driver.Value, error)
pkg database/sql, type NullByte struct
pkg database/sql, type NullByte struct, Byte uint8
pkg database/sql, type NullByte struct, Valid bool

The zoneinfo.zip archive contains time zone files compiled using
the code and data maintained as part of the IANA Time Zone Database.
The IANA asserts that the database is in the public domain.

For more information, see
https://www.iana.org/time-zones
ftp://ftp.iana.org/tz/code/tz-link.html
https://datatracker.ietf.org/doc/html/rfc6557

pkg crypto/x509, type RevocationList struct, ThisUpdate time.Time
pkg database/sql, method (*DB) SetConnMaxIdleTime(time.Duration)
pkg database/sql, method (*Row) Err() error
pkg database/sql, type DBStats struct, MaxIdleTimeClosed int64
pkg database/sql/driver, type Validator interface { IsValid }
pkg database/sql/driver, type Validator interface, IsValid() bool

	Host               xnet.URL `json:"host"`
	Port               string   `json:"port"`
	User               string   `json:"user"`
	Password           string   `json:"password"`
	Database           string   `json:"database"`
	QueueDir           string   `json:"queueDir"`
	QueueLimit         uint64   `json:"queueLimit"`
	MaxOpenConnections int      `json:"maxOpenConnections"`
}

// Validate MySQLArgs fields

pkg database/sql, method (*Conn) QueryRowContext(context.Context, string, ...interface{}) *Row
pkg database/sql, method (*DB) Conn(context.Context) (*Conn, error)
pkg database/sql, type Conn struct
pkg database/sql, type Out struct
pkg database/sql, type Out struct, Dest interface{}
pkg database/sql, type Out struct, In bool
pkg database/sql, var ErrConnDone error

---> 100%
```

</div>

## 创建 SQLAlchemy 部件

让我们转到文件`sql_app/database.py`。

### 导入 SQLAlchemy 部件

```Python hl_lines="1-3"
{!../../docs_src/sql_databases/sql_app/database.py!}
```

### 为 SQLAlchemy 定义数据库 URL地址

```Python hl_lines="5-6"
{!../../docs_src/sql_databases/sql_app/database.py!}
```

在这个例子中，我们正在“连接”到一个 SQLite 数据库（用 SQLite 数据库打开一个文件）。

package migrator

import (
	"database/sql"
	"reflect"
)

// ColumnType column type implements ColumnType interface
type ColumnType struct {
	SQLColumnType      *sql.ColumnType
	NameValue          sql.NullString
	DataTypeValue      sql.NullString
	ColumnTypeValue    sql.NullString
	PrimaryKeyValue    sql.NullBool
	UniqueValue        sql.NullBool
	AutoIncrementValue sql.NullBool
	LengthValue        sql.NullInt64

                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "description": "Query string for the items to search in the database that have a good match",
                            "required": False,
                            "deprecated": True,
                            "schema": IsDict(
                                {

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder`

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.

For example, it doesn't receive `datetime` objects, as those are not compatible with JSON.