Scripts are parsed by invoking the Parse method of T-SQL script DOM library TSqlParser class. The parser understands the complex T-SQL abstract syntax tree and splits T-SQL source into atomic TSqlParserTokens of TSqlTokenTypes that represent keywords, identifiers, punctuation, literals, whitespace, etc. These low-level tokens are grouped into more meaningful TSqlFragment objects that represent language elements of the script DOM, such as batches, statements, clauses, etc. Fragments, rather than the low-level parser tokens, are most often used in practice, although the underlying tokens are available for specialized requirements
The Parse method returns a TSqlFragment object of type TSqlScript containing all fragments within the script. This top-level fragment of the DOM hierarchy provides programmatic access to all language element fragments in the script. Nearly 1,000 different fragment types exist today due to the many granular T-SQL language elements.
Dan provides several examples of how to use the script DOM, making this a must-read if you’re interested in writing code around SQL Server.