Client and Web Interfaces to RDBMS

This chapter discusses ways in which more complex client applications can be written. These programs use SQL to select, insert, delete, or update tables in the database. Depending on the computer language used for the client program, a variety of interface libraries is available. 

One disadvantage of using client programs is that data must be transferred to and from the server. Depending on how much data is required, this can cause a client program to run less efficiently than a server function run as an extension of the RDBMS. 

Most new client programs will benefit from a judicious use of both new server-side SQL functions and new client functions. It is wise to carefully consider which operations are best done on the RDBMS server and which are done using a client program. There are several suggestions to consider in designing the best system for a project. 

The following suggestions may help design and implement a better system for a project needing a client interface. 

Consider extending SQL with new functions. This might be considered the fundamental suggestion in this book. There are many useful functions built into SQL, but sometimes a simple extension function can allow an SQL operation to run completely on the database server without having to pass data to the client. For example, to sort selected rows by and value in a column requires only simple SQL. If the data needed to sort the rows is not part of data being selected, consider writing a function that will provide the value to be sorted. For example, if it were necessary to sort by the number of atoms in a molecule, a natoms (smiles) function could be used in the order clause of SQL. 

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