If you wanted to connect MS SQL server using Oracle SQL developer client please follow the below steps.(I specified the steps w.r.t Ubunthu platform)
1. Install oracle SQL developer client
Download the package mentioned in the Oracle Website. If you are using ubunthu try Other platform options.
Extract the package and make sqldeveloper.sh as executable and run ./sqldeveloper.sh. It will ask for the JDK path mention it correctly.
Now the GUI will open up.
2. In case you are not finding the MS SQL Server option ?
1. Install oracle SQL developer client
Download the package mentioned in the Oracle Website. If you are using ubunthu try Other platform options.
Extract the package and make sqldeveloper.sh as executable and run ./sqldeveloper.sh. It will ask for the JDK path mention it correctly.
Now the GUI will open up.
2. In case you are not finding the MS SQL Server option ?
JDBC driver is required for connecting to MS SQL server. Please follow the below steps mentioned in this link