Text operators in a relational programming language

JRelix is an implementation of a relational database system which provides a significantly powerful database programming language and which is especially adept with complex data. This thesis documents an enhancement of JRelix which provides intuitive descriptions and efficient manipulations for textual information in the database.Coupled with the relational and domain algebra in JRelix, the new database system supports rapid textual information retrieval, flexible text mining, structured text schema discovery, relational operations on text, transformation between text and relation, and powerful pattern matching in structured or unstructured data. These endow JRelix with the capacity of handling complicated textual information from heterogeneous data sources (e.g., data from the web), and also enrich its searching power on vast bodies of electronic data as a text/relational database management system