for _, v := range []byte(sql) {
			if v == '?' {
				if len(vars) > idx {
					newSQL.WriteString(vars[idx])
					idx++
					continue
				}
			}
			newSQL.WriteByte(v)
		}

		sql = newSQL.String()
	} else {
		sql = numericPlaceholder.ReplaceAllString(sql, "$$$1$$")

		sql = numericPlaceholderRe.ReplaceAllStringFunc(sql, func(v string) string {
			num := v[1 : len(v)-1]

		es                 = ExampleStruct{Name: "test", Val: "test"}
		intVal   intType   = 1
		floatVal floatType = 1.23
	)

	results := []struct {
		SQL           string
		NumericRegexp *regexp.Regexp
		Vars          []interface{}
		Result        string
	}{
		{
			SQL:           "create table users (name, age, height, actived, bytes, create_at, update_at, deleted_at, email, role, pass) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",

jflute <******@****.***> 1437804256 +0900

Shinsuke Sugaya <******@****.***> 1436049991 +0900

```Python hl_lines="4  14  16-22"
{!../../../docs_src/async_sql_databases/tutorial001.py!}
```

!!! tip
    👀 👈 🌐 👉 📟 😁 🇸🇲 🐚.

    `databases` 🚫 🔨 🕳 📥.

## 🗄 & ⚒ 🆙 `databases`

* 🗄 `databases`.
* ✍ `DATABASE_URL`.
* ✍ `database` 🎚.

```Python hl_lines="3  9  12"
{!../../../docs_src/async_sql_databases/tutorial001.py!}
```

!!! tip

Sebastián Ramírez <******@****.***> 1641564691 +0100

# 异步 SQL 关系型数据库

**FastAPI** 使用 <a href="https://github.com/encode/databases" class="external-link" target="_blank">`encode/databases`</a> 为连接数据库提供异步支持（`async` 与 `await`）。

`databases` 兼容以下数据库：

* PostgreSQL
* MySQL
* SQLite

本章示例使用 **SQLite**，它使用的是单文件，且 Python 内置集成了 SQLite，因此，可以直接复制并运行本章示例。

生产环境下，则要使用 **PostgreSQL** 等数据库服务器。

!!! tip "提示"

Later, for your production application, you might want to use a database server like **PostgreSQL**.

!!! tip
    You could adopt ideas from the section about SQLAlchemy ORM ([SQL (Relational) Databases](../tutorial/sql-databases.md){.internal-link target=_blank}), like using utility functions to perform operations in the database, independent of your **FastAPI** code.

Sebastián Ramírez <******@****.***> 1641564691 +0100

Harsha Laxman <******@****.***> 1687432812 -0700