Class PreparedStatement

Represents a prepared statement, a query with bound variables that has been prepared (pre-parsed) by the database.

A prepared statement can be executed once concrete values has been provided for the bound variables. The pair of a prepared statement and values for its bound variables is a BoundStatement and can be executed (by Session#Execute).

Inheritance

object

PreparedStatement

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Cassandra

Assembly: Cassandra.dll

Syntax

public class PreparedStatement

Constructors

PreparedStatement()

Initializes a new instance of the Cassandra.PreparedStatement class

Declaration

public PreparedStatement()

Properties

ConsistencyLevel

Gets the default consistency level for all executions using this instance

Declaration

public ConsistencyLevel? ConsistencyLevel { get; }

Property Value

Type	Description
ConsistencyLevel?

IncomingPayload

Gets the the incoming payload, that is, the payload that the server sent back with its prepared response, or null if the server did not include any custom payload.

Declaration

public IDictionary<string, byte[]> IncomingPayload { get; }

Property Value

Type	Description
IDictionary<string, byte[]>

IsIdempotent

Determines if the query is idempotent, i.e. whether it can be applied multiple times without changing the result beyond the initial application.

Idempotence of the prepared statement plays a role in ISpeculativeExecutionPolicy. If a query is not idempotent, the driver will not schedule speculative executions for it.

When the property is null, the driver will use the default value from the GetDefaultIdempotence().

Declaration

public bool? IsIdempotent { get; }

Property Value

Type	Description
bool?

OutgoingPayload

Gets custom payload for that will be included when executing an Statement.

Declaration

public IDictionary<string, byte[]> OutgoingPayload { get; }

Property Value

Type	Description
IDictionary<string, byte[]>

RoutingIndexes

Gets or sets the parameter indexes that are part of the partition key

Declaration

public int[] RoutingIndexes { get; }

Property Value

Type	Description
int[]

RoutingKey

Gets the routing key for the prepared statement.

Declaration

public RoutingKey RoutingKey { get; }

Property Value

Type	Description
RoutingKey

Variables

Gets metadata on the bounded variables of this prepared statement.

Declaration

public RowSetMetadata Variables { get; }

Property Value

Type	Description
RowSetMetadata

Methods

Bind(params object[])

Creates a new BoundStatement instance with the provided parameter values.

You can specify the parameter values by the position of the markers in the query, or by name using a single instance of an anonymous type, with property names as parameter names.

Note that while no more values than bound variables can be provided, it is allowed to provide less values that there is variables.

You can provide a comma-separated variable number of arguments to the Bind() method. When providing an array, the reference might be used by the driver making it not safe to modify its content.

Declaration

public virtual BoundStatement Bind(params object[] values)

Parameters

Type	Name	Description
object[]	values	The values to bind to the variables of the newly created BoundStatement.

Returns

Type	Description
BoundStatement	The newly created BoundStatement with the query parameters set.

Examples

Binding different parameters:

PreparedStatement ps = session.Prepare("INSERT INTO table (id, name) VALUES (?, ?)");
BoundStatement statement = ps.Bind(Guid.NewGuid(), "Franz Ferdinand");
session.Execute(statement);

SetConsistencyLevel(ConsistencyLevel)

Sets a default consistency level for all BoundStatement created from this object.

If no consistency level is set through this method, the BoundStatement created from this object will use the default consistency level (One).

Changing the default consistency level is not retroactive, it only applies to BoundStatement created after the change.

Declaration

public PreparedStatement SetConsistencyLevel(ConsistencyLevel consistency)

Parameters

Type	Name	Description
ConsistencyLevel	consistency	the default consistency level to set.

Returns

Type	Description
PreparedStatement	this PreparedStatement object.

SetIdempotence(bool)

Sets whether the prepared statement is idempotent.

Idempotence of the query plays a role in ISpeculativeExecutionPolicy. If a query is not idempotent, the driver will not schedule speculative executions for it.

Declaration

public PreparedStatement SetIdempotence(bool value)

Parameters

Type	Name	Description
bool	value

Returns

Type	Description
PreparedStatement

SetOutgoingPayload(IDictionary<string, byte[]>)

Sets a custom outgoing payload for this statement. Each time an statement generated using this prepared statement is executed, this payload will be included in the request. Once it is set using this method, the payload should not be modified.

Declaration

public PreparedStatement SetOutgoingPayload(IDictionary<string, byte[]> payload)

Parameters

Type	Name	Description
IDictionary<string, byte[]>	payload

Returns

Type	Description
PreparedStatement

SetRoutingKey(params RoutingKey[])

Set the routing key for this query.

The routing key is a hint for token aware load balancing policies but is never mandatory. This method allows you to manually provide a routing key for this query.

Use this method ONLY if the partition keys are the same for all query executions (hard-coded parameters).

If the partition key is composite, you should provide multiple routing key components.

Declaration

public PreparedStatement SetRoutingKey(params RoutingKey[] routingKeyComponents)

Parameters

Type	Name	Description
RoutingKey[]	routingKeyComponents	the raw (binary) values to compose to obtain the routing key.

Returns

Type	Description
PreparedStatement	this PreparedStatement object.

SetRoutingNames(params string[])

For named query markers, it sets the parameter names that are part of the routing key.

Use this method ONLY if the parameter names are different from the partition key names.

Declaration

public PreparedStatement SetRoutingNames(params string[] names)

Parameters

Type	Name	Description
string[]	names

Returns

Type	Description
PreparedStatement	this PreparedStatement object.