com.amazon.redshift.core.Query Maven / Gradle / Ivy
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/*
* Copyright (c) 2004, PostgreSQL Global Development Group
* See the LICENSE file in the project root for more information.
*/
// Copyright (c) 2004, Open Cloud Limited.
package com.amazon.redshift.core;
import java.util.Map;
/**
* Abstraction of a generic Query, hiding the details of any protocol-version-specific data needed
* to execute the query efficiently.
*
* Query objects should be explicitly closed when no longer needed; if resources are allocated on
* the server for this query, their cleanup is triggered by closing the Query.
*
* @author Oliver Jowett ([email protected])
*/
public interface Query {
/**
* Create a ParameterList suitable for storing parameters associated with this Query.
*
* If this query has no parameters, a ParameterList will be returned, but it may be a shared
* immutable object. If this query does have parameters, the returned ParameterList is a new list,
* unshared by other callers.
*
* @return a suitable ParameterList instance for this query
*/
ParameterList createParameterList();
/**
* Stringize this query to a human-readable form, substituting particular parameter values for
* parameter placeholders.
*
* @param parameters a ParameterList returned by this Query's {@link #createParameterList} method,
* or null to leave the parameter placeholders unsubstituted.
* @return a human-readable representation of this query
*/
String toString(ParameterList parameters);
/**
* Returns SQL in native for database format.
* @return SQL in native for database format
*/
String getNativeSql();
/**
* Returns properties of the query (sql keyword, and some other parsing info).
* @return returns properties of the query (sql keyword, and some other parsing info) or null if not applicable
*/
SqlCommand getSqlCommand();
/**
* Close this query and free any server-side resources associated with it. The resources may not
* be immediately deallocated, but closing a Query may make the deallocation more prompt.
*
* A closed Query should not be executed.
*/
void close();
boolean isStatementDescribed();
boolean isEmpty();
/**
* Get the number of times this Query has been batched.
* @return number of times addBatch() has been called.
*/
int getBatchSize();
/**
* Get a map that a result set can use to find the index associated to a name.
*
* @return null if the query implementation does not support this method.
*/
Map getResultSetColumnNameIndexMap();
/**
* Return a list of the Query objects that make up this query. If this object is already a
* SimpleQuery, returns null (avoids an extra array construction in the common case).
*
* @return an array of single-statement queries, or null if this object is already a
* single-statement query.
*/
Query[] getSubqueries();
}