*** DRAFT ***

SQLite Requirement Matrix Details
fts3.html

Index Summary Markup Original


R-40630-02268-40288-03121-46855-38283-56768-00095 tcl slt th3 src

If used within a SELECT that uses the "query by rowid" or "linear scan" strategies, then the snippet and offsets both return an empty string, and the matchinfo function returns a blob value zero bytes in size.

tcl/fts3snippet.test:436

/* IMP: R-40630-02268 */
# EVIDENCE-OF: R-40630-02268 If used within a SELECT that uses the
# "query by rowid" or "linear scan" strategies, then the snippet and
# offsets both return an empty string, and the matchinfo function
# returns a blob value zero bytes in size.

R-30140-15527-13572-28268-32284-47435-56739-50325 tcl slt th3 src

The compress option is used to specify the compress function.

/* IMP: R-30140-15527 */
# EVIDENCE-OF: R-30140-15527 The compress option is used to specify the
# compress function.

R-19570-53558-20410-64757-41149-53677-54257-63723 tcl slt th3 src

It is an error to specify a compress function without also specifying an uncompress function.

/* IMP: R-19570-53558 */
# EVIDENCE-OF: R-19570-53558 It is an error to specify a compress
# function without also specifying an uncompress function.

R-33708-43819-48693-15112-15003-18731-38490-26979 tcl slt th3 src

The content allows the text being indexed to be stored in a separate table distinct from the FTS4 table, or even outside of SQLite.

/* IMP: R-33708-43819 */
# EVIDENCE-OF: R-33708-43819 The content allows the text being indexed
# to be stored in a separate table distinct from the FTS4 table, or even
# outside of SQLite.

R-03650-18079-61121-63570-57348-35510-07530-48237 tcl slt th3 src

The languageid option causes the FTS4 table to have an additional hidden integer column that identifies the language of the text contained in each row.

/* IMP: R-03650-18079 */
# EVIDENCE-OF: R-03650-18079 The languageid option causes the FTS4 table
# to have an additional hidden integer column that identifies the
# language of the text contained in each row.

R-31509-21858-22614-04075-64482-13479-08451-58532 tcl slt th3 src

The "order" option may be set to either "DESC" or "ASC" (in upper or lower case).

/* IMP: R-31509-21858 */
# EVIDENCE-OF: R-31509-21858 The "order" option may be set to either
# "DESC" or "ASC" (in upper or lower case).

R-18879-47479-26487-44670-60127-29624-08821-22011 tcl slt th3 src

If it is set to "DESC", then FTS4 stores its data in such a way as to optimize returning results in descending order by docid.

/* IMP: R-18879-47479 */
# EVIDENCE-OF: R-18879-47479 If it is set to "DESC", then FTS4 stores
# its data in such a way as to optimize returning results in descending
# order by docid.

R-15704-22093-19659-04811-31747-18777-12777-21799 tcl slt th3 src

If it is set to "ASC" (the default), then the data structures are optimized for returning results in ascending order by docid.

/* IMP: R-15704-22093 */
# EVIDENCE-OF: R-15704-22093 If it is set to "ASC" (the default), then
# the data structures are optimized for returning results in ascending
# order by docid.

R-10734-24248-12820-36089-32208-53594-64364-42192 tcl slt th3 src

In other words, if many of the queries run against the FTS4 table use "ORDER BY docid DESC", then it may improve performance to add the "order=desc" option to the CREATE VIRTUAL TABLE statement.

/* IMP: R-10734-24248 */
# EVIDENCE-OF: R-10734-24248 In other words, if many of the queries run
# against the FTS4 table use "ORDER BY docid DESC", then it may improve
# performance to add the "order=desc" option to the CREATE VIRTUAL TABLE
# statement.

R-22517-03298-06877-11770-25908-54043-03696-50918 tcl slt th3 src

The FTS4 prefix option causes FTS to index term prefixes of specified lengths in the same way that it always indexes complete terms.

/* IMP: R-22517-03298 */
# EVIDENCE-OF: R-22517-03298 The FTS4 prefix option causes FTS to index
# term prefixes of specified lengths in the same way that it always
# indexes complete terms.

R-00888-53115-42960-22822-38463-42827-06390-25797 tcl slt th3 src

The prefix option must be set to a comma separated list of positive non-zero integers.

/* IMP: R-00888-53115 */
# EVIDENCE-OF: R-00888-53115 The prefix option must be set to a comma
# separated list of positive non-zero integers.

R-00918-16997-33541-06619-01421-44106-53820-17907 tcl slt th3 src

For each value N in the list, prefixes of length N bytes (when encoded using UTF-8) are indexed.

/* IMP: R-00918-16997 */
# EVIDENCE-OF: R-00918-16997 For each value N in the list, prefixes of
# length N bytes (when encoded using UTF-8) are indexed.

R-29005-40549-62573-61718-07162-40054-58592-42696 tcl slt th3 src

FTS4 uses term prefix indexes to speed up prefix queries.

/* IMP: R-29005-40549 */
# EVIDENCE-OF: R-29005-40549 FTS4 uses term prefix indexes to speed up
# prefix queries.