In order to perform linguistic queries on documents, you must create linguistic output tables and then generate the output for the text column. Figure 2 shows the relationship between the tables containing the document text and the linguistic output tables. You use the ConText Server to generate linguistic output from text documents and store it as structured data in output tables. Then you use the Oracle7 Server to query the tables directly, providing fast access to themes and Gists. The ConText Server has a large knowledgebase of the English language that it uses to classify a document by its major themes.
Themes present a profile of the main subjects or topics of a document.
In essence, they provide a quick snapshot of what the document is about. Up to 16 themes are generated for each document, and each theme is assigned a relative weight that measures the strength of the theme relative to the other themes in the document. A Gist is a summary of a document and consists of selected paragraphs that reflect the themes of the document. Whole paragraphs are used to create Gists in order to maintain continuity and provide context. The following statements show how to create the linguistic output tables for themes and Gists.