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MongoDB C++ Driver
legacy-1.1.2
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Represents a Mongo query expression. More...
#include <dbclientinterface.h>
Public Member Functions | |
| Query & | sort (const BSONObj &sortPattern) |
| Add a sort (ORDER BY) criteria to the query expression. More... | |
| Query & | sort (const std::string &field, int asc=1) |
| Add a sort (ORDER BY) criteria to the query expression. More... | |
| Query & | hint (BSONObj keyPattern) |
| Provide a hint to the query. More... | |
| Query & | maxTimeMs (int millis) |
| Specifies a cumulative time limit in milliseconds for processing an operation. More... | |
| Query & | minKey (const BSONObj &val) |
| Provide min and/or max index limits for the query. More... | |
| Query & | maxKey (const BSONObj &val) |
| max is exclusive | |
| Query & | explain () |
| Return explain information about execution of this query instead of the actual query results. More... | |
| Query & | snapshot () |
| Use snapshot mode for the query. More... | |
| Query & | where (const std::string &jscode, BSONObj scope) |
| Queries to the Mongo database support a $where parameter option which contains a javascript function that is evaluated to see whether objects being queried match its criteria. More... | |
| Query & | readPref (ReadPreference pref, const BSONArray &tags) |
| Sets the read preference for this query. More... | |
| bool | isComplex (bool *hasDollar=0) const |
Static Public Member Functions | |
| static bool MONGO_CLIENT_FUNC | hasReadPreference (const BSONObj &queryObj) |
Represents a Mongo query expression.
Typically one uses the MONGO_QUERY(...) macro to construct a Query object. Examples: MONGO_QUERY( "age" << 33 << "school" << "UCLA" ).sort("name") MONGO_QUERY( "age" << GT << 30 << LT << 50 )
| Query& mongo::Query::explain | ( | ) |
Return explain information about execution of this query instead of the actual query results.
Normally it is easier to use the mongo shell to run db.find(...).explain().
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static |
Provide a hint to the query.
| keyPattern | Key pattern for the index to use. Example: hint("{ts:1}") |
| bool mongo::Query::isComplex | ( | bool * | hasDollar = 0 | ) | const |
| Query& mongo::Query::maxTimeMs | ( | int | millis | ) |
Specifies a cumulative time limit in milliseconds for processing an operation.
MongoDB will interrupt the operation at the earliest following interrupt point.
Provide min and/or max index limits for the query.
min <= x < max
Sets the read preference for this query.
| pref | the read preference mode for this query. |
| tags | the set of tags to use for this query. |
| Query& mongo::Query::snapshot | ( | ) |
Use snapshot mode for the query.
Snapshot mode assures no duplicates are returned, or objects missed, which were present at both the start and end of the query's execution (if an object is new during the query, or deleted during the query, it may or may not be returned, even with snapshot mode).
Note that short query responses (less than 1MB) are always effectively snapshotted.
Currently, snapshot mode may not be used with sorting or explicit hints.
Add a sort (ORDER BY) criteria to the query expression.
| sortPattern | the sort order template. For example to order by name ascending, time descending: { name : 1, ts : -1 } i.e. BSON( "name" << 1 << "ts" << -1 ) or fromjson(" name : 1, ts : -1 ") |
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inline |
Add a sort (ORDER BY) criteria to the query expression.
This version of sort() assumes you want to sort on a single field.
| asc | = 1 for ascending order asc = -1 for descending order |
Queries to the Mongo database support a $where parameter option which contains a javascript function that is evaluated to see whether objects being queried match its criteria.
Use this helper to append such a function to a query object. Your query may also contain other traditional Mongo query terms.
| jscode | The javascript function to evaluate against each potential object match. The function must return true for matched objects. Use the this variable to inspect the current object. |
| scope | SavedContext for the javascript object. List in a BSON object any variables you would like defined when the jscode executes. One can think of these as "bind variables". |
Examples: conn.findOne("test.coll", Query("{a:3}").where("this.b == 2 || this.c == 3")); Query badBalance = Query().where("this.debits - this.credits < 0");
1.8.10
