Use text search features in Cloud Firestore to search for specific strings within a collection.
Before you begin
Before you start using text searches, do the following:
-
Ensure that you have access to an existing MongoDB compatible operations database, or Create a database and connect to it .
-
Ensure that you have a text index, or Create a text index .
Run a text search
Text searches use the $text
operator inside a filter.
Specify the queried string in the $search
argument.
Run a general text search
Run the following command to perform a general text search:
# Find search
db.cities.find ({
$text
:
{
$search
:
"french bread"
}
})
# Aggregation search
db.cities.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"french bread"
}
}
}
])
;
If your index is partitioned, then you can filter based on the partition by
including the partition in an "and" equality filter within your search.
For example, if you had a city
partition, you could filter a text search as
follows:
db.myCollection.find (
{
$and
:
[
{
$text
:
{
$search
:
"french bread"
}
}
,
{
"city"
:
"Paris"
}
]
}
)
You can also filter an aggregation based on a partition. For example:
db.myCollection.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"french bread"
}
}
}
,
{
"city"
:
"Paris"
}
]
)
;
The value of your partition must be a string. Your partition filter must be joined to your text search by using an "and".
Set the text search language
You can set the text search language using the $language
argument. For
example:
db.cities.find ({
$text
:
{
$search
:
"french bread"
,
$language
:
"en"
}
})
If you don't set a language, then the search uses the language of the text index.
Search for an exact term
To search for an exact term, configure the term as a sequence of words enclosed by double quotes. For example:
# Find search
db.cities.find ({
$text
:
{
$search
:
"\"best french bread\""
}
})
# Aggregation search
db.cities.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"\"best french bread\""
}
}
}
,
])
;
Search for a term combination
To make your text search more precise, specify a chain of terms. For example, the following search returns documents that match the combination best AND french AND ("bread" OR "is"):
# Find search
db.cities.find ({
$text
:
{
$search
:
"\"best\" \"french\" bread is"
}
})
# Aggregation search
db.cities.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"\"best\" \"french\" bread is"
}
}
}
,
])
;
Exclude a term
To exclude a term from a text search, prefix the term with a hyphen (-):
# Find search
db.cities.find ({
$text
:
{
$search
:
"best bread -french"
}
})
# Aggregation search
db.cities.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"best bread -french"
}
}
}
,
])
;
Calculate relevance score
Use the {$meta: "textScore"}
expression to calculate the relevance score of
the documents matched by the text search. To sort the results in descending
score order, use $meta
in a sort expression. Consider the following examples,
where SCORE_FIELD
is the name of the field used to store the score
value:
# Find search
db.cities
.find ({
$text
:
{
$search
:
"best french bread"
}
})
.sort ({
SCORE_FIELD
:
{
$meta
:
"textScore"
}
})
# Aggregation search
db.cities.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"best french bread"
}
}
}
,
{
$sort
:
{
" SCORE_FIELD
"
:
{
$meta
:
"textScore"
}
}
}
,
])
;
You can also use text score in projection expressions. For example:
# Find search
db.cities
.find ({
$text
:
{
$search
:
"best french bread"
}
})
.project ({
score:
{
$meta
:
"textScore"
}
})
# Aggregation search
db.cities.aggregate ([
{
$match
:
{
$text
:
{
$search
:
"best french bread"
}
}
}
,
{
$project
:
{
"scoreField"
:
{
$meta
:
"textScore"
}
}
}
,
])
;
Expand search
To enhance the relevance of text search outcomes, the $text
operator augments
the search string according to the specified language to include matches for
context-aware synonyms, stemmed forms, spelling-corrected terms,
diacritic variations and more.
Limitations
-
$nearoperators and$textoperators can't be used in the same the text search. - A single
$textoperator is permitted perfindoraggregationsearch. - In aggregations, the
$matchstage with$textmust be the first pipeline stage. -
$textcan only be nested inside$andand$or. - If
$textis inside$or, the non-search disjuncts may use existing ordered indexes to optimize the search. If the other disjuncts are not indexed, then the search relies on a collection scan. -
$textcannot be used with hints. - Queries with text search can't sort by
$natural.
