Integrate almost any SQL Server feature through custom code using the programming models and interfaces. Each feature area includes native and managed APIs used for data collection, data access, server administration, or data visualization.
SQL Server 2016 Developer Edition (Free!)
SQL Server Management Studio (SSMS) is a free integrated environment for working with SQL Server, and releases updated versions almost monthly, so visit the SSMS download page for the latest version.
SQL Server Data Tools (SSDT) is also free, and works best with Visual Studio. Visit the SSDT download page for the latest version, where you can also get the free version of Visual Studio 2015 Community.