We don't offer Drop Database in nCluster and other postgresql variant DBs b/c of the 1 conn per DB limit. You are not allowed to drop a database if you have a currently open connection to that DB. By using the schema browser, the app has already created a conn to that DB. Hence, it is not possible to drop a DB via Schema Browser. This is why we don't provide the Drop DB option.

 I am confused because of two things:

1.when we right click on database->select script object to window as, it gives  drop option

2.when we select multiple databases-> right click on them, it gives  delete option

so why we have provided those two options ??

1.when we right click on database->select script object to window as, it gives  drop option

This action simply generates a script. It doesn't execute the script. A use case for this would be that a user could copy the content of this script and then open a query analyzer window to a different DB and execute this script from a different DB connection.  The exact steps are: 1) use schema browser to right click on DB & generate drop script. 2) Open a query analyzer window to a different DB. 3) From schema browser, right click on registered server and choose "disconnect" action. 4) execute drop script from query analyzer

2.when we select multiple databases-> right click on them, it gives  delete option

This is an artifact of how ADS works. When you choose multiple items and then right click, we pop-up a generic menu which doesn't take into account the business logic rules of which DBs can & cannot be dropped. It's possible that you select one DB from server Oracle and second DB from server nCluster. So our code always shows the drop option. If you were to execute the drop action, you'll notice that if you had an open connection, the nCluster one would fail.