Extensions to SQL for Chemical Structures

Standard SQL data types, such as integers, float, and text, are useful for storing scientific data, such as counts, measurements, and names. 

Operators, such as +, 11 and functions such as sqrt, round, and upper can be used with these data types. SQL has the ability to search data, using functions such as =, , and the like. The goal of the SQL extensions is to enable SMILES to be handled as readily as any standard data type. This requires that SQL be extended to validate and standardize, or canon-icalize SMARTS. In addition, these SQL extensions provide functions and operators to allow comparisons and searches of molecular structures stored as SMILES. 

The cansmiles function should also be used to insert each SMILES when a table is created. For example  

Insert Into structures (cansmi) Values cansmiles( CC(O)C )  

The cansmiles function can also be used to enforce an SQL constraint that the cansmi column must contain valid canonical SMILES. SQL constrains like this are commonly used to maintain data integrity. For example, the SQL clause check (cansmi = cansmiles (cansmi)) can be used in the initial creation of the table. One might also consider using an SQL trigger to handle an insert or update to a column that is required to contain canonical SMILES. 

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