Support for the Contains Operator of Each Source Type

The syntax of the search language on non-structured data used with the contains operator is described in the section Syntax of Search Expressions for the Contains Operator. However, bear in mind that the search options available depend on the capacities natively provided by the data source. For example, Google Search does not support different characteristics of the search language such as proximity searches. Therefore, when the contains operator is used with attributes from those sources, these capacities will not be available.

This section provides exact details as to the search capacities supported for each source type. These capacities are also specified in the Configuration Properties of each data source (see section CONTAINS Operator Configuration Properties) that can be consulted using the DESC VIEW statement (see section Describing Catalog Elements).

The data sources Aracne-type (see section Denodo Aracne Data Sources), Google Search (see Google Search Data Sources) and Custom (see Custom Data Sources) can use the contains operator.

The following sections describe the capacities supported for Aracne and Google Search wrappers, respectively. Custom-type wrappers can specify the capacities supported through the Configuration Properties (see section CONTAINS Operator Configuration Properties and section Describing Catalog Elements).

Aracne

The following characteristics of the contains operator search language are not supported in Denodo Aracne-type sources:

  • The wildcards ? and * cannot appear in the first position of a term.
  • Searches using the proximity operator ~ must specify the maximum number of words that can separate the terms of the phrase.
  • The logic operator NOT must appear at the same level as a logic operator AND. Example: The search (term1 AND NOT term2) would work correctly, but not the search (term1 OR NOT term2).

The remaining capacities of the search language are supported in Denodo Aracne-type sources.