https://msdn.microsoft.com/en-gb/library/system.data.sqlclient.sqlconnection.connectionstring.aspx https://msdn.microsoft.com/en-us/library/jj653752(v=vs.110).aspx
<?xml version="1.0"?>
<configuration>
<connectionStrings>
<add name="ConnectionString_LocalDB" providerName="System.Data.SqlClient"
connectionString="Data Source=(LocalDB)\MSSQLLocalDB; InitialCatalog=DatabaseName; Integrated Security=True; MultipleActiveResultSets=True" />
<add name="ConnectionString_SQLEXPRESS" providerName="System.Data.SqlClient"
connectionString="Data Source=.\SQLEXPRESS; Initial Catalog=DatabaseName; Integrated Security=True; MultipleActiveResultSets=True" />
<add name="ConnectionString_SQLEXPRESS_App_Data" providerName="System.Data.SqlClient"
connectionString="Data Source=.\SQLEXPRESS; AttachDbFileName=|DataDirectory|\DatabaseFileName.mdf; Integrated Security=True; User Instance=True; MultipleActiveResultSets=True" />
<add name="ConnectionString_SQLServer" providerName="System.Data.SqlClient"
connectionString="Data Source=ServerName; Initial Catalog=DatabaseName; Integrated Security=False; User Id=userid; Password=password; MultipleActiveResultSets=True" />
<add name="ConnectionString_SQLServer_Integrated_Security" providerName="System.Data.SqlClient"
connectionString="Data Source=ServerName\InstanceName; Initial Catalog=DatabaseName; Integrated Security=True; MultipleActiveResultSets=True" />
<add name="ConnectionString_Azure" providerName="System.Data.SqlClient"
connectionString="Data Source=tcp:ServerName.database.windows.net,1433; Initial Catalog=DatabaseName; Integrated Security=False; User Id=username@servername; Password=password; Encrypt=True; TrustServerCertificate=False; MultipleActiveResultSets=True" />
<add name="ConnectionString_Common" providerName="System.Data.SqlClient"
connectionString="Data Source=(LocalDB)\MSSQLLocalDB; InitialCatalog=DatabaseName; Integrated Security=True; MultipleActiveResultSets=True" />
<add name="ConnectionString_Common2" providerName="System.Data.SqlClient"
connectionString="Server=(LocalDB)\MSSQLLocalDB; Database=DatabaseName; Trusted_Connection=True; MultipleActiveResultSets=True" />
</connectionStrings>
</configuration>