We study the data models WP and AWP that have been widely used for many years in the area of Information Retrieval. WP and AWP can be used to represent and query textual information under the Boolean model using the concepts of attributes with values of type text, and word proximity constraints. Variations of WP and AWP are in use in most deployed digital libraries using the Boolean model, text extenders for relational database systems (e.g., Oracle Text) and the search engine Altavista. We present the syntax, semantics and model theory of WP and AWP and analyze the complexity of query satisfiability and entailment. Since word proximity constraints are very similar to temporal constraints, the techniques we use in our analysis are similar to the ones developed in previous work on first-order theories of temporal constraints and temporal constraint databases.