If the data source has a large number of objects, you can limit the number of object names that are retrieved by typing one or more letters in the Filter field and choosing Apply Filter. Available Items displays the objects that have names that begin with the same letter or letters that you typed. You also can use SQL filter characters for the database that you are using. For example, on some databases, an underscore (_) matches any single character, and the percent sign (%) matches any sequence of characters.
For some databases, if a table or column name contains spaces or SQL reserved words, you must enclose the name in quotation marks (" "). If you drag and drop tables and columns, and those items need to be enclosed in double quotation marks, select the Use identifier quoting option. When this option is selected, the data set editor inserts the quotation marks around a table or column name when you drop it in the text area.