21. OEQMols and Queries in OEChem

By this point, the use of OEMols and OEGraphMols should be familiar subjects. If they are not, please review the section entitled Getting Started with OEChem Molecule found in the introductory chapter as well as the chapter entitled OEMols and OEGraphMols.

It is not uncommon in chemical informatics to consider the equivalence of the graph which represents a molecule and the graph which represents a substructure query. Indeed the simplest of queries are molecules themselves. If one considers each node (or atom) as a potentially complex atom query, even highly complex queries can be represented as molecules.

In OEChem, this concept of a query as a molecule is represented by the OEQMolBase abstract base-class. An OEQMolBase contains OEQAtomBase and OEQBondBase atom and bond representations. These versions of OEChem atoms and bonds manage the atom and bond matches which comprise the query.

OEChem defines a the concrete OEQMol class which provides a programmer access to the API defined by the OEQMolBase class. This is analogous to the way in which OEMols and OEGraphMols, provide concrete access to the OEMCMolBaseT and OEMolBase APIs.

Simplistic OEChem inheritance scheme:
                OEBase
                  |
                  |
                OEMolBase ---------------- OEGraphMol
                  |
                  |
                OEQMolBase --------------- OEQMol
<- indicates inheritance
-- indicates API correspondence without inheritance

				OEChem - C++ Theory Manual Version 1.3.1

				OEChem - C++ Theory Manual Version 1.3.1