MongoDB\Driver\Server::executeReadCommand
Execute a database command that reads on this server
Description
final public MongoDB\Driver\Cursor MongoDB\Driver\Server::executeReadCommand(string $db, MongoDB\Driver\Command $command, arraynull $options = null)
This method will apply logic that is specific to commands that read (e.g.
» distinct).
Default values for the "readPreference" and
"readConcern" options will be inferred from an active
transaction (indicated by the "session" option), followed
by the 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.
Parameters
-
db (string)
-
The name of the database on which to execute the command.
-
command (MongoDB\Driver\Command)
-
The command to execute.
-
options
-
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.
|
Warning
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.
Return Values
Returns MongoDB\Driver\Cursor on success.
Errors/Exceptions
- Throws MongoDB\Driver\Exception\InvalidArgumentException if the
"session" option is used with an associated transaction in combination with a "readConcern" or "writeConcern" option.
- Throws MongoDB\Driver\Exception\InvalidArgumentException on argument parsing errors.
- Throws MongoDB\Driver\Exception\ConnectionException if connection to the server fails (for reasons other than authentication).
- Throws MongoDB\Driver\Exception\AuthenticationException if authentication is needed and fails.
- Throws MongoDB\Driver\Exception\RuntimeException on other errors (e.g. invalid command).
See Also
- MongoDB\Driver\Command
- MongoDB\Driver\Cursor
- MongoDB\Driver\Server::executeCommand
- MongoDB\Driver\Server::executeReadWriteCommand
- MongoDB\Driver\Server::executeWriteCommand
- MongoDB\Driver\Manager::executeReadCommand