sys.dm_fts_index_keywords_by_document (Transact-SQL)
Returns information about the document-level content of a full-text index associated with the specified table.
sys.dm_fts_index_keywords_by_document is a dynamic management function.
To view higher-level full-text index information
To view information about property-level content related to a document property
Składnia
sys.dm_fts_index_keywords_by_document
(
DB_ID('database_name'), OBJECT_ID('table_name')
)
Arguments
db_id('database_name')
A call to the DB_ID() function. This function accepts a database name and returns the database ID, which sys.dm_fts_index_keywords_by_document uses to find the specified database. If database_name is omitted, the current database ID is returned.object_id('table_name')
A call to the OBJECT_ID() function. This function accepts a table name and returns the table ID of the table containing the full-text index to inspect.
Table Returned
Column |
Data type |
Description |
|---|---|---|
keyword |
nvarchar(4000) |
The hexadecimal representation of the keyword that is stored inside the full-text index.
|
display_term |
nvarchar(4000) |
The human-readable format of the keyword. This format is derived from the internal format that is stored in the full-text index.
|
column_id |
int |
ID of the column from which the current keyword was full-text indexed. |
document_id |
int |
ID of the document or row from which the current term was full-text indexed. This ID corresponds to the full-text key value of that document or row. |
occurrence_count |
int |
Number of occurrences of the current keyword in the document or row that is indicated by document_id. When 'search_property_name' is specified, occurrence_count displays only the number of occurrences of the current keyword in the specified search property within the document or row. |
Uwagi
The information returned by sys.dm_fts_index_keywords_by_document is useful for finding out the following, among other things:
The total number of keywords that a full-text index contains.
Whether a keyword is part of a given document or row.
How many times a keyword appears in the whole full-text index; that is:
(SUM(occurrence_count) WHERE keyword=keyword_value )
How many times a keyword appears in a given document or row.
How many keywords a given document or row contains.
Also, you can also use the information provided by sys.dm_fts_index_keywords_by_document to retrieve all the keywords belonging to a given document or row.
When the full-text key column is an integer data type, as recommended, the document_id maps directly to the full-text key value in the base table.
In contrast, when the full-text key column uses a non-integer data type, document_id does not represent the full-text key in the base table. In this case, to identify the row in the base table that is returned by dm_fts_index_keywords_by_document, you need to join this view with the results returned by sp_fulltext_keymappings. Before you can join them, you must store the output of the stored procedure in a temp table. Then you can join the document_id column of dm_fts_index_keywords_by_document with the DocId column that is returned by this stored procedure. Note that a timestamp column cannot receive values at insert time, because they are auto-generated by SQL Server. Therefore, the timestamp column must be converted to varbinary(8) columns. The following example shows these steps. In this example, table_id is the ID of your table, database_name is the name of your database, and table_name is the name of your table.
USE database_name;
GO
CREATE TABLE #MyTempTable
(
docid INT PRIMARY KEY ,
[key] INT NOT NULL
);
DECLARE @db_id int = db_id(N'database_name');
DECLARE @table_id int = OBJECT_ID(N'table_name');
INSERT INTO #MyTempTable EXEC sp_fulltext_keymappings @table_id;
SELECT * FROM sys.dm_fts_index_keywords_by_document
( @db_id, @table_id ) kbd
INNER JOIN #MyTempTable tt ON tt.[docid]=kbd.document_id;
GO
Permissions
Requires SELECT permission on the columns covered by the full-text index and CREATE FULLTEXT CATALOG permissions.
Examples
A. Displaying full-text index content at the document level
The following example displays the content of the full-text index at the document level in the HumanResources.JobCandidate table of the AdventureWorks sample database.
[!UWAGA]
You can create this index by executing the example provided for the HumanResources.JobCandidate table in CREATE FULLTEXT INDEX (Transact-SQL).
SELECT * FROM sys.dm_fts_index_keywords_by_document(db_id('AdventureWorks'),
object_id('HumanResources.JobCandidate'));
GO
Zobacz także
Odwołanie
Full-Text Search and Semantic Search Dynamic Management Views and Functions (Transact-SQL)
sys.dm_fts_index_keywords (Transact-SQL)
sys.dm_fts_index_keywords_by_property (Transact-SQL)
sp_fulltext_keymappings (Transact-SQL)