Perl::DBI

Sometimes these general-purpose applications are not sufficiently specific to the needs of database users. In that case, custom applications can be written. Many programming languages have extensions that allow data to be selected from the database and read into data structures for further operations. This chapter considers ways of using ODBC (Open Database Correctivity), JDBC for Java, Perl DBI (Database Interface), pg and pgdb for Python, and PDO for PHP... 

Perl DBI module. http //search.cpan.org/ timb/DBI/DBI.pm (accessed April 18, 2008). 

In order for the code to be applicable to mixtures consisting of a wide and expandable number of compounds, we decided to store all data in a relational database and to provide a variety of access methods to that database. In fact, any database that can be accessed by Perl-DBI or ODBC methods (which include all major commercial and open source products) can be used to store compound data. Since many of these databases are network-accessible, the HCToolkit framework can be driven by a common institution-wide (or multi-institution) database to ensure consistency of properties and mixtures in a calculation. We also store mixture information in the database to ease collaboration in studying specific compositions. Hence, all researchers in a specific institution can connect to the same database, and all can use consistent fluid compositions (e.g. fluid 72 ) in numeric simulations. 

After the SQL statement is executed, an array reference is returned using fetchall arraryref. The individual rows from this array are then printed. Some care needs to be taken when using fetchall arrayref when a large number of rows are returned. In that case, not all rows may be returned and the function will need to be called again until all rows are returned. The documentation for the DBI perl module discusses this more fully.1... 

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