Database connection string settings when dnn is installed

I recently came into contact with dnn and thought it was something.
There are many installation websites for dnn Article. I'm installing my first dnn ProgramAlthough I read those articles, it still doesn't help. Sometimes, my system configuration is different from others.

When installing the dnn program, the database that comes with the program is the sqlexpress database. If sqlexpress is installed on your system, the connection string is consistent with the default one:
<Add name = "sitesqlserver" connectionstring = "Data Source =./sqlexpress; Integrated Security = true;User instance = true; Attachdbfilename = E: \ Smith \ dnnlearning \ app_data \ database. MDF; "providername =" system. Data. sqlclient "/>
If sql2005 is installed on your system, change the connection string slightly:
<Add name = "sitesqlserver" connectionstring = "Data Source = cq14; Integrated Security = true;User instance = false; Attachdbfilename = E: \ Smith \ dnnlearning \ app_data \ database. MDF; "providername =" system. Data. sqlclient "/>

Of course, there are other writing methods for sql2005 connection strings, which I will not talk about here. In fact, the key setting here is the setting of the user instance. This concept was not clear at first, so it took a lot of detours. User instance = false indicates that the connection is switched from the default SQL Server express to the instance running in the current user account. If sql2005 is installed, set it to false.