See the Web page for using the Chothia assignment software for further details. Parameters are placed in parentheses. The select statement may extend over more than one line. These test words are all equivalent and are the minimum string required. String values do not need to be placed in inverted commas unless they include white space or inverted commas.
All comparisons ignore case.
Each clause generates a set which matches the specified test and places the set on a stack. The logical operators AND, OR and NOT cause operations to be performed on this stack of sets. The stack has a maximum depth of 10 items. This should be more than enough for all likely queries providing that the logical operators are not all placed at the end of the statement. The maximum stack depth is set at 10.