I've downloaded and installed SQL Server 2014 Express on Windows 10, I've been through this loop at least 3 times now. The installation completes without warnings or errors. I have chosen to use Window authentication. I'm trying to use HeidiSQL to connect to SQL Server. I already have MariaDB installation and am able to connect to that using HeidiSQL.
When I connect to MariaDB I am able to select Databases from the drop down combo, but not for SQL Server. I don't seem to be able to connect with HeidiSQL.
In HeidiSQL, the settings are:
I can't select a Database, if I click on the Open button after a while it comes up with:
SQL Error(17): [DBNETLIB]ConnectionOpen (COnnect()).]SQL does not exist or access denied SQL Server does not exist or access denied.
In order to use HeidiSQL's network type Microsoft SQL Server (TCP/IP), you need to activate TCP/IP protocol in your MSSQL configuration.
Further on, I am unsure if Windows authentication worked for me, as I'm always using the default SA user, which is created while installing SQL Server.
Apart from that, you should be able to connect using <yourmachine>\SQLEXPRESS on port 1433.