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Overview |
To access databases in Go, you use a sql.DB. You use this type to create
statements and transactions, execute queries, and fetch results.
要在Go中访问数据库，请使用sql.DB.您可以使用此类型来创建语句和事务，执行查询以及获取结果。
The first thing you should know is that a sql.DB isn't a database
connection. It also doesn't map to any particular database software's notion
of a "database" or "schema." It's an abstraction of the interface and existence
of a database, which might be as varied as a local file, accessed through a network
connection, or in-memory and in-process.
您应该知道的第一件事是sql.DB不是数据库连接。它也没有映射到任何特定的数据库软件的“数据库”或“模式”的概念。它是接口的抽象和数据库的存在，它可以像通过网络连接访问的本地文件一样多样化，或者在内存中和进程中。
sql.DB performs some important tasks for you behind the scenes:
- It opens and closes connections to the actual underlying database, via the driver.
- It manages a pool of connections as needed, which may be a variety of things as mentioned.
The sql.DB abstraction is designed to keep you from worrying about how to
manage concurrent access to the underlying datastore. A connection is marked
in-use when you use it to perform a task, and then returned to the available
pool when it's not in use anymore. One consequence of this is that if you fail
to release connections back to the pool, you can cause sql.DB to open a lot of
connections, potentially running out of resources (too many connections, too
many open file handles, lack of available network ports, etc). We'll discuss
more about this later.
sql.DB 抽象旨在避免担心如何管理对底层数据存储的并发访问。当您使用连接执行任务时，连接将被标记为正在使用，然后在不再使用时返回到可用池。这样做的一个结果是，如果您无法将连接释放回池，则可能导致 sql.DB 打开大量连接，可能耗尽资源（连接太多，打开文件句柄太多，缺少可用网络）港口等）。我们稍后会详细讨论这个问题。
After creating a sql.DB, you can use it to query the database that it
represents, as well as creating statements and transactions.
创建sql.DB之后，您可以使用它来查询它所代表的数据库，以及创建语句和事务。