SqlLocalDB工具的一些有趣发现

本文只是记录个人使用SqlLocalDB过程中的一些有趣现象，并不一定适用所有情况。关于SqlLocalDB的简介及相应命令行工具的具体使用，参见: SQL Server LocalDB 入门 及 SqlLocalDB Utility。

1. 当本地安装多个版本的SQL Server LocalDB时，无法创建低版本的名为MSSQLLocalDB的默认实例(注: LocalDB的第一个版本是SQL Server 2012, 默认实例名是v11.0, 从SQL Server 2014开始，默认实例名修改成了MSSQLLocalDB), 也无法通过指定Version创建该默认实例。但是不指定Version或者通过SSMS连接(localdb)\MSSQLLocalDB却可以创建该实例。

   C:\>SqlLocalDB versions
   Microsoft SQL Server 2016 (13.1.4001.0)
   Microsoft SQL Server 2017 (14.0.1000.169)
   
   C:\>SqlLocalDB info
   MSSQLLocalDB
   ProjectsV13
   
   C:\>SqlLocalDB delete MSSQLLocalDB
   Delete of LocalDB instance "MSSQLLocalDB" failed because of the following error:
   The specified LocalDB instance does not exist.
   
   C:\>SqlLocalDB create MSSQLLocalDB 13.1
   Creation of LocalDB instance "MSSQLLocalDB" failed because of the following error:
   The parameter for the LocalDB Instance API method is incorrect. Consult the API documentation.
   
   C:\>SqlLocalDB create MSSQLLocalDB 13.1.4001.0
   Creation of LocalDB instance "MSSQLLocalDB" failed because of the following error:
   The parameter for the LocalDB Instance API method is incorrect. Consult the API documentation.
   
   C:\>SqlLocalDB create MSSQLLocalDB 14.0
   Creation of LocalDB instance "MSSQLLocalDB" failed because of the following error:
   The parameter for the LocalDB Instance API method is incorrect. Consult the API documentation.
   
   C:\>SqlLocalDB create MSSQLLocalDB 14.0.1000.169
   Creation of LocalDB instance "MSSQLLocalDB" failed because of the following error:
   The parameter for the LocalDB Instance API method is incorrect. Consult the API documentation.
   
   C:\>SqlLocalDB create MSSQLLocalDB
   LocalDB instance "MSSQLLocalDB" created with version 14.0.1000.169.
   

2. 虽然安装了多个版本的SQL Server LocalDB, 但是却不能创建同名实例，试着创建同名实例，返回消息也不一样。

   C:\>SqlLocalDB create MyDataBase 13.1
   LocalDB instance "MyDataBase" created with version 13.1.4001.0.
   
   C:\>SqlLocalDB create MyDataBase 14.0
   Creation of LocalDB instance "MyDataBase" failed because of the following error:
   Unable to create the LocalDB instance with specified version. An instance with the same name already exists, but it has lower version than the specified version.
   
   C:\>SqlLocalDB create MySQLDB
   LocalDB instance "MySQLDB" created with version 14.0.1000.169.
   
   C:\>SqlLocalDB create MySQLDB 13.1.4001.0
   LocalDB instance "MySQLDB" created with version 14.0.1000.169.
   
   C:\>SqlLocalDB info
   MSSQLLocalDB
   MyDataBase
   MySQLDB
   ProjectsV13
   
   C:\>SqlLocalDB info MyDataBase
   Name:               MyDataBase
   Version:            13.1.4001.0
   Shared name:
   Owner:              XXXXXXXXXX
   Auto-create:        No
   State:              Stopped
   Last start time:    2020/8/23 11:14:50
   Instance pipe name:
   
   C:\>SqlLocalDB info MySQLDB
   Name:               MySQLDB
   Version:            14.0.1000.169
   Shared name:
   Owner:              XXXXXXXXXX
   Auto-create:        No
   State:              Stopped
   Last start time:    2020/8/23 11:15:42
   Instance pipe name:
   

3. 无意中发现，原来CMD也支持管道，好吧, 认知再一次被刷新(另: 默认实例MSSQLLocalDB的Auto-create属性是Yes, 其他的是No)！

   C:\>SqlLocalDB info MSSQLLocalDB | sort
   Auto-create:        Yes
   Instance pipe name:
   Last start time:    2020/8/23 10:56:20
   Name:               MSSQLLocalDB
   Owner:              XXXXXXXXXX
   Shared name:
   State:              Stopped
   Version:            14.0.1000.169
   
   C:\>SqlLocalDB info | sort
   MSSQLLocalDB
   MyDataBase
   MySQLDB
   ProjectsV13