pkg crypto/x509, type OID struct #60665
pkg database/sql, method (*Null[$0]) Scan(interface{}) error #60370
pkg database/sql, method (Null[$0]) Value() (driver.Value, error) #60370
pkg database/sql, type Null[$0 interface{}] struct #60370
pkg database/sql, type Null[$0 interface{}] struct, V $0 #60370
pkg database/sql, type Null[$0 interface{}] struct, Valid bool #60370

---> 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）。

) -> AsyncGenerator[_T, None]:
    # blocking __exit__ from running waiting on a free thread
    # can create race conditions/deadlocks if the context manager itself
    # has its own internal pool (e.g. a database connection pool)
    # to avoid this we let __exit__ run without a capacity limit
    # since we're creating a new limiter for each call, any non-zero limit
    # works (1 is arbitrary)
    exit_limiter = CapacityLimiter(1)

class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():

package utils

import (
	"database/sql"
	"database/sql/driver"
	"errors"
	"math"
	"strings"
	"testing"
	"time"
)

func TestIsValidDBNameChar(t *testing.T) {
	for _, db := range []string{"db", "dbName", "db_name", "db1", "1dbname", "db$name"} {
		if fields := strings.FieldsFunc(db, IsValidDBNameChar); len(fields) != 1 {
			t.Fatalf("failed to parse db name %v", db)
		}
	}
}

func TestCheckTruth(t *testing.T) {

package clause

import (
	"database/sql"
	"database/sql/driver"
	"go/ast"
	"reflect"
)

// Expression expression interface
type Expression interface {
	Build(builder Builder)
}

// NegationExpressionBuilder negation expression builder
type NegationExpressionBuilder interface {
	NegationBuild(builder Builder)
}

// Expr raw expression
type Expr struct {
	SQL                string
	Vars               []interface{}

pkg database/sql, method (IsolationLevel) String() string
pkg database/sql, type DBStats struct, Idle int
pkg database/sql, type DBStats struct, InUse int
pkg database/sql, type DBStats struct, MaxIdleClosed int64
pkg database/sql, type DBStats struct, MaxLifetimeClosed int64
pkg database/sql, type DBStats struct, MaxOpenConnections int
pkg database/sql, type DBStats struct, WaitCount int64

For example, you could want to **return a dictionary** or a database object, but **declare it as a Pydantic model**. This way the Pydantic model would do all the data documentation, validation, etc. for the object that you returned (e.g. a dictionary or database object).

      go install github.com/microsoft/go-sqlcmd/cmd/sqlcmd@latest || true
      SQLCMDPASSWORD=LoremIpsum86 sqlcmd -U sa -S localhost:9930 -Q "IF DB_ID('gorm') IS NULL CREATE DATABASE gorm" > /dev/null || true
      SQLCMDPASSWORD=LoremIpsum86 sqlcmd -U sa -S localhost:9930 -Q "IF SUSER_ID (N'gorm') IS NULL CREATE LOGIN gorm WITH PASSWORD = 'LoremIpsum86';" > /dev/null || true

a [web server](https://fess.codelibs.org/14.17/admin/webconfig-guide.html), [file system](https://fess.codelibs.org/14.17/admin/fileconfig-guide.html), or [Data Store](https://fess.codelibs.org/14.17/admin/dataconfig-guide.html) (such as a CSV or database). Many file formats are supported including (but not limited to): Microsoft Office, PDF, and zip.

*[Fess Site Search](https://github.com/codelibs/fess-site-search)* is a free alternative to [Google Site Search](https://enterprise.google...