JSDoc: Class: Metadata

new Metadata(options, controlConnection)

Represents cluster and schema information. The metadata class acts as a internal state of the driver.

Parameters:

Name	Type	Description
`options`	ClientOptions
`controlConnection`	ControlConnection	Control connection used to retrieve information.

Methods

clearPrepared()

Clears the internal state related to the prepared statements. Following calls to the Client using the prepare flag will re-prepare the statements.

getAggregate(keyspaceName, name, signature, callbackopt)

Gets a definition of CQL aggregate for a given name and signature.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

When trying to retrieve the same aggregate definition concurrently, it will query once and invoke all callbacks with the retrieved information.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace
`name`	String		Name of the aggregate
`signature`	Array.<String> \| Array.<{code, info}>		Array of types of the parameters.
`callback`	function	<optional>	The callback with the err as a first parameter and the Aggregate as second parameter.

getAggregates(keyspaceName, name, callbackopt)

Gets the definition of CQL aggregate for a given name.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

When trying to retrieve the same aggregates definition concurrently, it will query once and invoke all callbacks with the retrieved information.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace
`name`	String		Name of the Function
`callback`	function	<optional>	The callback with the err as a first parameter and the array of Aggregate as second parameter.

getFunction(keyspaceName, name, signature, callbackopt)

Gets a definition of CQL function for a given name and signature.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

When trying to retrieve the same function definition concurrently, it will query once and invoke all callbacks with the retrieved information.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace
`name`	String		Name of the Function
`signature`	Array.<String> \| Array.<{code, info}>		Array of types of the parameters.
`callback`	function	<optional>	The callback with the err as a first parameter and the SchemaFunction as second parameter.

getFunctions(keyspaceName, name, callbackopt)

Gets the definition of CQL functions for a given name.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

When trying to retrieve the same function definition concurrently, it will query once and invoke all callbacks with the retrieved information.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace.
`name`	String		Name of the Function.
`callback`	function	<optional>	The callback with the err as a first parameter and the array of SchemaFunction as second parameter.

getMaterializedView(keyspaceName, name, callbackopt)

Gets the definition of a CQL materialized view for a given name.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

Note that, unlike the rest of the Metadata methods, this method does not cache the result for following calls, as the current version of the Cassandra native protocol does not support schema change events for materialized views. Each call to this method will produce one or more queries to the cluster.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace
`name`	String		Name of the materialized view
`callback`	function	<optional>	The callback with the err as a first parameter and the MaterializedView as second parameter.

getReplicas(keyspaceName, tokenBuffer) → {Array}

Gets the host list representing the replicas that contain such partition.

It uses the pre-loaded keyspace metadata to retrieve the replicas for a token for a given keyspace. When the keyspace metadata has not been loaded, it returns null.

Parameters:

Name	Type	Description
`keyspaceName`	String
`tokenBuffer`	Buffer

Returns:

Type: Array

getTable(keyspaceName, name, callbackopt)

Gets the definition of a table.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

When trying to retrieve the same table definition concurrently, it will query once and invoke all callbacks with the retrieved information.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace.
`name`	String		Name of the Table.
`callback`	function	<optional>	The callback with the err as a first parameter and the TableMetadata as second parameter.

getTrace(traceId, callbackopt)

Gets the trace session generated by Cassandra when query tracing is enabled for the query. The trace itself is stored in Cassandra in the sessions and events table in the system_traces keyspace and can be retrieve manually using the trace identifier.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

Parameters:

Name	Type	Attributes	Description
`traceId`	Uuid		Identifier of the trace session.
`callback`	function	<optional>	The callback with the err as first parameter and the query trace as second parameter.

getUdt(keyspaceName, name, callbackopt)

Gets the definition of an user-defined type.

If a callback is provided, the callback is invoked when the metadata retrieval completes. Otherwise, it returns a Promise.

When trying to retrieve the same UDT definition concurrently, it will query once and invoke all callbacks with the retrieved information.

Parameters:

Name	Type	Attributes	Description
`keyspaceName`	String		Name of the keyspace.
`name`	String		Name of the UDT.
`callback`	function	<optional>	The callback to invoke when retrieval completes.

refreshKeyspace(name, callbackopt)

Gets the keyspace metadata information and updates the internal state of the driver.

If a callback is provided, the callback is invoked when the keyspaces metadata refresh completes. Otherwise, it returns a Promise.

Parameters:

Name	Type	Attributes	Description
`name`	String		Name of the keyspace.
`callback`	function	<optional>	Optional callback.

refreshKeyspaces(waitReconnectopt, callbackopt)

Gets the metadata information of all the keyspaces and updates the internal state of the driver.

If a callback is provided, the callback is invoked when the keyspace metadata refresh completes. Otherwise, it returns a Promise.

Parameters:

Name	Type	Attributes	Description
`waitReconnect`	Boolean \| function	<optional>	Determines if it should wait for reconnection in case the control connection is not connected at the moment. Default: true.
`callback`	function	<optional>	Optional callback.