Procedural language

Programming language.s. Traditional procedural languages do not provide the necessary constructs for implementing sequence logic. This necessitates one of the following ... 

Procedural languages for scientific computation are briefly reviewed and contrasted wiA declarative languages. The capabilities of TKISolver are explained, and two examples of its use in chemical computations are given. 

In all of diese procedural languages (also called imperative languages (2), one of the basic elements of syntax is the assignment statement, in which an algebraic... 

English - Flowchart language -> Procedural language -> machine language... 

The RDBMS is installed and runs on a computer that functions as a database server. Any SQL commands are executed on the server by the RDBMS. Functions written in SQL or in any of the procedural languages mentioned above are also executed by the RDBMS. This has the advantage that the data tables used by these SQL commands or procedural functions are under the control of the server. This is the most efficient way to access the data. The disadvantage is that the server may have many requests to handle from many users. Another way to operate on data tables is indirectly, using a client program typically (although not necessarily) run from another computer. 

There is a smaller set of tools that are typically run on the server. Any SQL commands and any procedural language functions are run on the server. In principle, there is complete flexibility of the server side tools, since in principle any computer program can be written in any computer language. Later chapters of this book show how the RDBMS server itself can be extended using server side programming to handle chemical information. These extensions may directly solve the needs of a particular project, but more importantly they increase the flexibility of the RDBMS to handle chemical information. Client programs can use the results of chemical searches and other computations as well. 

Unlike the procedural languages discussed above, C language functions are compiled separately. The code itself is not included in the SQL create function command. Instead, the create function command refers to a compiled object such as shared object (.so) file located in some directory on the server running the RDBMS. For example, the CHORD oe smiles function is defined as follows. 

This defines the SQL function oe smiles, which is realized by calling the C function oe anysmiles in the shared object file gnova.so. The definition of the input arguments and return values is done in the same way as for a function written in any other procedural language. 

Relational databases are not just for storage and organization of information. While they have always provided useful tools to search data, I now realize how the extensibility of a database increases its usefulness by using various procedural languages operating within the database. I have converted most of my essential tools into database functions. Whenever possible, these tools operate on whole tables rather than processing them using arrays and iterators. It seems now that I am inside the database... 

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