Increasing Performance of Regular Expressions in VBA

February 12, 2013 in VBA

In a previous post I presented some general-purpose wrappers for adding regular expressions functionality to VBA and SQL in Microsoft Access. These wrappers work well, but we can make them much more efficient for situations where the same pattern is used many times, such as in a SQL query where the regular expression will be executed on each row of the input table or query. Caching Compiled Regular Expressions What we’ll use is the fact that, behind the scenes, every regular expression pattern gets compiled into a tiny little program that executes in order to actually apply the regular expression.
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Regular Expressions in VBA

February 8, 2013 in VBA

A frequent question for most database platforms is how to use regular expressions in SQL queries. Regular expressions are an awesome tool for working with text and are built in to just about every widely used programming language, but are not standardized in SQL. Sometimes relational databases are employed to work on chunks of text and having regular expressions available is mighty helpful. Oracle supports regular expressions natively as does Teradata 14 (first released in February 2012), but most other database platforms require some sort of extensibility mechanism. For SQL Server you have to build CLR wrappers, in DB2 and
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