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Extending HCL OneDB™Beyond standard relational database objects, HCL OneDB™ can be extended to handle specialized data types, access methods, routines, and other objects. HCL OneDB™ includes many built-in extensions that are fully integrated in the database server. HCL OneDB™ also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for HCL OneDB™.
HCL OneDB™ extensions and DataBlade® modulesThese topics describe how to use built-in database extensions and separately installed DataBlade® modules.
Excalibur Text Search DataBlade® Module User's GuideThese topics describe the module and how to access and use its components.
OverviewThis section provides an overview of the module.
Components of the Excalibur Text Search DataBlade® moduleThe module has three principal components: the etx access method, the etx_contains() operator, and the supporting routines defined for the DataBlade® module.
The etx access methodUse the etx access method to call on the Excalibur Text Retrieval Library to create indexes that support sophisticated searches on table columns that contain text. The indexes that you create with the etx access method are called etx indexes.
Data typesTo take advantage of the etx access method, you must store the text data you want to search in a column of type BLOB, CLOB, LVARCHAR, CHAR, VARCHAR, IfxDocDesc, or IfxMRData.

Data types

To take advantage of the etx access method, you must store the text data you want to search in a column of type BLOB, CLOB, LVARCHAR, CHAR, VARCHAR, IfxDocDesc, or IfxMRData.

If most of your documents are large (over 32 KB), store them in columns of type BLOB or CLOB. If your documents contain binary data, such as proprietary formatting information from word-processing programs such as Microsoft™ Word, store them in columns of type BLOB. If your documents contain only standard ASCII character data, such as HTML pages, store them in columns of type CLOB.

If all your documents are smaller than 32 KB and do not contain any binary data, consider storing the documents in columns of type LVARCHAR.

Columns of type CHAR or VARCHAR are limited in the amount of information they can hold and are not adequate for large documents. Columns of these two data types are useful for descriptive information, such as titles and names. You can also create etx indexes on tables that contain legacy data in CHAR or VARCHAR columns.

IfxDocDesc and IfxMRData types are designed specifically for use with text access methods. The IfxDocDesc data type enables you to store documents in either the database or in the operating system file system. IfxMRData is a multirepresentational data type, which means that the data type itself decides whether to store your document as an LVARCHAR or as a smart large object, depending on the initial size of the document.

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