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ConText Index Tables and Indexes


This appendix contains detailed information about the database tables and Oracle indexes that are created by ConText when a text or theme index is created for a column.

The following topics are covered in this appendix:

ConText Index Tables

ConText index tables are created automatically by ConText during text and theme indexing. The five digit number nnnnn is the identifier for the policy that owns the index. Each of the ConText index tables for a policy has the same five digit identifier.


Note:

The ConText index tables are internal tables and should not be accessed directly. To perform administrative tasks on a ConText index, use the CTX_DDL and CTX_DML packages or the System Administration tool.

 

DR_nnnnn_I1Tn

This is the main table of a ConText index. It stores each indexed token from the text column, as well as a reference to the documents in which the word occurs and the location of each occurrence.

The n appended to the end of the table name is an internal identifier (value of 1 or 2) which ConText uses to prevent table name collisions when two-table compaction or two-table combined real deletion and compaction are used to optimize the ConText index for a table.


Note:

The appended n is transparent to users because a synonym called DR_nnnnn_I1T, which points to DR_nnnnn_I1Tn, is automatically updated after two-table index optimization.

For more information about two-table index optimization, see "Index Optimization" in Chapter 6, "Text Concepts".

 

Name   Type   Description  

WORD_TEXT

 

VARCHAR2(64)

 

Indexed word

 

FIRST_DOC

 

NUMBER(38)

 

DOCID of first document in WORD_INFO

 

DOCLSIZE

 

NUMBER(38)

 

Size, in bytes, of WORD_INFO string

 

WORD_TYPE

 

NUMBER(3)

 

Identifier for type of word (internal use only)

 

WORD_INFO

 

LONG RAW

 

String identifying DOCIDs for all documents in which the indexed word occurs and location of each occurrence.

 

DR_nnnnn_KTB

This internal table maps the textkey for each indexed document to a document identifier (DOCID). ConText indexes use DOCIDs internally to identify the documents in which indexed words occur. ConText indexes also use DOCIDs to track documents that have been deleted or modified through a DML action.

Name   Type   Description  

TEXTKEY

 

VARCHAR2(256)

 

ID for document in text table

 

DOCID

 

NUMBER(38)

 

ID for document in index

 

DR_nnnnn_LST

This internal table generates the unique document IDs (DOCID) used in a ConText index. It also stores the next available DOCID and the DOCIDs of documents that have been modified or deleted from the text table.

Name   Type   Description  

SID

 

NUMBER(38)

 

Audit session ID of the ConText server which is currently creating an index

 

IDCOUNT

 

NUMBER(38)

 

Maximum value for DOCIDs

 

LTYPE

 

VARCHAR2(32)

 

Status of DOCID in index:

F = Free, D = Deleted

 

CONTIGUOUS

 

NUMBER(2)

 

Indicates the range of DOCIDs is contiguous for the current indexing (ensures that no overlapping DOCIDs are used in index)

 

DATA

 

VARCHAR2(1024)

 

If LTYPE = F, DOCID for next insert;

If LTYPE = D, DOCID for deleted document

 

DR_nnnnn_NLT

This internal table is used to optimize DOCID resolution during queries.

Name   Type   Description  

FIRST_DOC

 

NUMBER(38)

 

Internal use only

 

IDLIST

 

LONG RAW

 

Internal use only

 

DR_nnnnn_I1W

This internal table stores each word identified by the Soundex function and the groups to which the word belongs. This table is only created when you index a table with a policy that includes Soundex (soundex_at_index attribute enabled for the GENERIC WORD LIST Tile).

Name   Type   Description  

WORD

 

VARCHAR2(15)

 

Word identified by Soundex

 

GROUP1

 

VARCHAR2(15)

 

ID for 1st Soundex group to which word belongs

 

GROUP2

 

VARCHAR2(15)

 

Reserved for future use

 

GROUP3

 

VARCHAR2(15)

 

Reserved for future use

 

Oracle Indexes for ConText Index Tables

The Oracle indexes for a ConText index are created automatically by ConText after the index tables have been populated with the ConText index information.

ConText creates a total of five Oracle indexes for the three ConText index tables created during indexing. The Oracle indexes follow the naming conventions used to name the index tables, where the five digit number nnnnn is the internal identifier for the policy that owns the ConText index.

SQR Table

The SQR table is created automatically by ConText during text and theme indexing of a text column; however, the table is not populated until a stored query expression (SQE) is created (stored) for the policy of the text column.

The five digit number nnnnn is the identifier for the policy that owns the SQE.


Note:

The SQR table is an internal table and should not be accessed directly. To perform administration tasks on an SQE, use the CTX_QUERY package or the System Administration tool.

For more information about creating SQEs and using the CTX_QUERY package, see Oracle ConText Option Application Developer's Guide.

 

DR_nnnnn_SQR

This internal table stores the results of an SQE. The definition of the SQE is stored in an internal table owned by CTXSYS.

Name   Type   Description  

QUERY_NAME

 

VARCHAR2(32)

 

Name of SQE

 

SESSION_ID

 

VARCHAR2(32)

 

SQE type (session or system)

 

FIRST_DOC

 

VARCHAR2(38)

 

DOCID for the first document retrieved by SQE

 

QUERY_RESULT

 

LONG RAW

 

Binary string containing results of SQE

 

Oracle Index for DR_nnnnn_SQR

During creation of the SQR table, an Oracle index, DR_nnnnn_SRI, is created on the table.




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