How can I set an on onListItemLongClick to list from database?

Question 1

You can implement it like this;

this.getListView().setLongClickable(true);
this.getListView().setOnItemLongClickListener(new OnItemLongClickListener() {
    public boolean onItemLongClick(AdapterView<?> parent, View v, int position, long id) {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(ctx);
    dialogBuilder.setTitle("Title");
    dialogBuilder.setMessage("Message?");
    dialogBuilder.setPositiveButton("Edit", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
               //Edit
        }
    });
    dialogBuilder.setNegativeButton("Delete", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
               //Delete
        }
    });
    dialogBuilder.create().show();
        return true;
    }
});

And you can use position as index to access list element.

Question 2

You need to add an OnItemLongClickListener for the ListView like this, So that when an item is long clicked onItemLongClick will be called

getListView().setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id)      { 
            // do your other stuff here based on the list item position
            return true;
        }
    });

Question 3

this.getListView().setLongClickable(true);
this.getListView().setOnItemLongClickListener(new OnItemLongClickListener() {
    public boolean onItemLongClick(AdapterView<?> parent, View v, int position, long id) {
        //set your dialog here
        return true;
    }
});

Question 4

Try this..

OnLongClickListener and getListView()

getListView().setOnLongClickListener(new View.OnLongClickListener() {

    @Override
    public boolean onLongClick(View v) {
        // TODO Auto-generated method stub
        Toast.makeText(getBaseContext(), "Long Clicked", Toast.LENGTH_SHORT).show();
        return true;
    }
});

EDIT

you can use Context Menu also refer below examples

How do you implement context menu in a ListActivity on Android?

Using contextmenu with listview in android

http://www.tktutorials.com/2013/06/android-context-menu-example.html