query provides --match_columns and --query parameters of select feature as function. You can specify multiple query functions in --filter parameter in select.
Because of such flexibility, you can control full text search behavior by combination of multiple query functions.
query can be used in only --filter in select.
query requires two arguments - match_columns and query_string.
The parameter query_expander or substitution_table is optional.
query(match_columns, query_string)
query(match_columns, query_string, query_expander)
query(match_columns, query_string, substitution_table)
Here are a schema definition and sample data to show usage.
Sample schema:
Execution example:
table_create Documents TABLE_NO_KEY
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Documents content COLUMN_SCALAR Text
# [[0, 1337566253.89858, 0.000355720520019531], true]
table_create Terms TABLE_PAT_KEY|KEY_NORMALIZE ShortText --default_tokenizer TokenBigram
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Terms documents_content_index COLUMN_INDEX|WITH_POSITION Documents content
# [[0, 1337566253.89858, 0.000355720520019531], true]
table_create Users TABLE_NO_KEY
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Users name COLUMN_SCALAR ShortText
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Users memo COLUMN_SCALAR ShortText
# [[0, 1337566253.89858, 0.000355720520019531], true]
table_create Lexicon TABLE_HASH_KEY ShortText \
--default_tokenizer TokenBigramSplitSymbolAlphaDigit \
--normalizer NormalizerAuto
column_create Lexicon users_name COLUMN_INDEX|WITH_POSITION Users name
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Lexicon users_memo COLUMN_INDEX|WITH_POSITION Users memo
# [[0, 1337566253.89858, 0.000355720520019531], true]
Sample data:
Execution example:
load --table Users
[
{"name": "Alice", "memo": "groonga user"},
{"name": "Alisa", "memo": "mroonga user"},
{"name": "Bob", "memo": "rroonga user"},
{"name": "Tom", "memo": "nroonga user"},
{"name": "Tobby", "memo": "groonga and mroonga user. mroonga is ..."},
]
# [[0, 1337566253.89858, 0.000355720520019531], true]
# [[0, 1337566253.89858, 0.000355720520019531], 5]
Here is the simple usage of query function which execute full text search by keyword 'alice' without using --match_columns and --query arguments in --filter.
Execution example:
select Users --output_columns name,_score --filter 'query("name * 10", "alice")'
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "name",
# "ShortText"
# ],
# [
# "_score",
# "Int32"
# ]
# ],
# [
# "Alice",
# 10
# ]
# ]
# ]
# ]
When executing above query, the keyword 'alice' is weighted to the value - '10'.
Here are the contrasting examples with/without query.
Execution example:
select Users --output_columns name,memo,_score --match_columns "memo * 10" --query "memo:@groonga OR memo:@mroonga OR memo:@user" --sortby -_score
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 5
# ],
# [
# [
# "name",
# "ShortText"
# ],
# [
# "memo",
# "ShortText"
# ],
# [
# "_score",
# "Int32"
# ]
# ],
# [
# "Tobby",
# "groonga and mroonga user. mroonga is ...",
# 4
# ],
# [
# "Alice",
# "groonga user",
# 2
# ],
# [
# "Alisa",
# "mroonga user",
# 2
# ],
# [
# "Bob",
# "rroonga user",
# 1
# ],
# [
# "Tom",
# "nroonga user",
# 1
# ]
# ]
# ]
# ]
In this case, the keywords 'groonga' and 'mroonga' and 'user' are given same weight value. You can't pass different weight value to each keyword in this way.
Execution example:
select Users --output_columns name,memo,_score --filter 'query("memo * 10", "groonga") || query("memo * 20", "mroonga") || query("memo * 1", "user")' --sortby -_score
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 5
# ],
# [
# [
# "name",
# "ShortText"
# ],
# [
# "memo",
# "ShortText"
# ],
# [
# "_score",
# "Int32"
# ]
# ],
# [
# "Tobby",
# "groonga and mroonga user. mroonga is ...",
# 51
# ],
# [
# "Alisa",
# "mroonga user",
# 21
# ],
# [
# "Alice",
# "groonga user",
# 11
# ],
# [
# "Tom",
# "nroonga user",
# 1
# ],
# [
# "Bob",
# "rroonga user",
# 1
# ]
# ]
# ]
# ]
On the other hand, by specifying multiple query, the keywords 'groonga' and 'mroonga' and 'user' are given different value of weight.
As a result, you can control full text search result by giving different weight to the keywords on your purpose.
There are two required parameter, match_columns and query_string.
Specifies the default target column for fulltext search by query_string parameter value. It is the same role as match_columns parameter in select.
Specifies the search condition in Query syntax. It is the same role as query parameter in select.
See match_columns about query parameter in select.
There are some optional parameters.
Specifies the plugin name for query expansion.
There is one plugin bundled in official release - QueryExpanderTSV.
See QueryExpanderTSV about details.
Specifies the substitution table and substitution column name by following format such as ${TABLE}.${COLUMN} for query expansion.
See query_expander about details.
query returns whether any record is matched or not. If one or more records are matched, it returns true. Otherwise, it returns false.