(mongodb >=1.4.0)
MongoDB\Driver\Server::executeReadCommand — Execute a database command that reads on this server
$db
, MongoDB\Driver\Command $command
[, array $options = array()
] )Executes the command on this server.
This method will apply logic that is specific to commands that read (e.g. » count) and take the MongoDB server version into account. The "readConcern" option will default to the corresponding value from the MongoDB Connection URI.
Note: The "readPreference" option does not control the server to which the driver issues the operation; it will always be executed on this server object. Instead, it may be used when issuing the operation to a secondary (from a replica set connection, not standalone) or mongos node to ensure that the driver sets the wire protocol accordingly or adds the read preference to the operation, respectively.
db (string)The name of the database on which to execute the command.
command (MongoDB\Driver\Command)The command to execute.
options
| Option | Type | Description |
|---|---|---|
| readConcern | MongoDB\Driver\ReadConcern |
A read concern to apply to the operation. This option is available in MongoDB 3.2+ and will result in an exception at execution time if specified for an older server version. |
| readPreference | MongoDB\Driver\ReadPreference |
A read preference to use for selecting a server for the operation. |
| session | MongoDB\Driver\Session |
A session to associate with the operation. |
If you are using a "session" which has a transaction in progress, you cannot specify a "readConcern" or "writeConcern" option. This will result in an MongoDB\Driver\Exception\InvalidArgumentException being thrown. Instead, you should set these two options when you create the transaction with MongoDB\Driver\Session::startTransaction().
Returns MongoDB\Driver\Cursor on success.