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/*-
* Copyright (C) 2011, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle NoSQL
* Database made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/nosqldb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle NoSQL Database for a copy of the license and
* additional information.
*/
package oracle.kv.query;
import java.util.Map;
import oracle.kv.KVStore;
import oracle.kv.table.FieldDef;
import oracle.kv.table.RecordDef;
/**
* Represents a {@link Statement} that has been compiled and an execution
* plan generated for it. A PreparedStatement should be used when it is
* expected that the same statement will be executed multiple times. This way,
* the cost of compilation is paid only once.
*
* An instance of PreparedStatement can be created via the
* {@link KVStore#prepare(String statement)} method. This instance can then be
* executed multiple times via one of the KVStore.execute methods (for example,
* {@link KVStore#execute(String statement, ExecuteOptions options)} or
* {@link KVStore#executeSync(Statement statement, ExecuteOptions options)}).
*
* If the statement is a DML statement that contains external variables,
* these variables must be bound to specific values before the statement can be
* executed. To allow for potentially concurrent execution of the same
* PreparedStatement multiple times with different bind values each time,
* binding of external variables must be done via one or more instances of
* the {@link BoundStatement} interface. Such instances are created via the
* #createBoundStatement() method. It is then the BoundStatement instances
* that must be executed (i.e., passed as input to the KVStore execute
* methods) instead of the PreparedStatement instance
*
* Objects implementing the PreparedStatement interface are thread-safe
* and their methods are re-entrant. On the other hand, {@link BoundStatement}
* instances are not thread-safe.
*
* @since 4.0
*/
public interface PreparedStatement extends Statement {
/**
* Returns the definition of the result of this Statement.
*/
RecordDef getResultDef();
/**
* Returns the types of the variables.
*/
Map getVariableTypes();
/**
* Returns the type of the given variableName or {@code null} if it
* doesn't exist.
*/
FieldDef getVariableType(String variableName);
/**
* Creates a new BoundStatement object for this PreparedStatement.
*/
BoundStatement createBoundStatement();
}