com.yahoo.bard.webservice.sql.helper

Class CalciteHelper

java.lang.Object

com.yahoo.bard.webservice.sql.helper.CalciteHelper

public class CalciteHelper
extends Object

Small utility class to help with connection to databases, building, and writing sql.

Constructor Summary

Constructors

Constructor and Description
CalciteHelper(DataSource dataSource) Initialize the helper with a datasource and it's schema.

Method Summary

Modifier and Type	Method and Description
static org.apache.calcite.tools.RelBuilder	getBuilder(DataSource dataSource, String schemaName) Creates a RelBuilder with the given schema.
Connection	getConnection() Creates a connection to the database from the dataSource.
org.apache.calcite.tools.RelBuilder	getNewRelBuilder(String schemaName) Creates a RelBuilder which can be used to build sql.
org.apache.calcite.rel.rel2sql.RelToSqlConverter	getNewRelToSqlConverter() Creates a new RelToSqlConverter using the dialect from the datasource this was constructed with.
org.apache.calcite.sql.pretty.SqlPrettyWriter	getNewSqlWriter() Creates a new SqlPrettyWriter using the dialect from the datasource this was constructed with.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CalciteHelper

public CalciteHelper(DataSource dataSource)
              throws SQLException

Initialize the helper with a datasource and it's schema.

Parameters:

dataSource - The datasource to make connections with.

Throws:

SQLException - if failed while making a connection to the database.

Method Detail

getNewRelBuilder

public org.apache.calcite.tools.RelBuilder getNewRelBuilder(String schemaName)

Creates a RelBuilder which can be used to build sql.

Parameters:

schemaName - The name of the schema that the tables are on.

Returns:

a RelBuilder or null if an error occurred.

getConnection

public Connection getConnection()
                         throws SQLException

Creates a connection to the database from the dataSource.

Returns:

the connection.

Throws:

SQLException - if can't create a connection.

getNewRelToSqlConverter

public org.apache.calcite.rel.rel2sql.RelToSqlConverter getNewRelToSqlConverter()

Creates a new RelToSqlConverter using the dialect from the datasource this was constructed with.

Returns:

a new converter.

getNewSqlWriter

public org.apache.calcite.sql.pretty.SqlPrettyWriter getNewSqlWriter()

Creates a new SqlPrettyWriter using the dialect from the datasource this was constructed with.

Returns:

a new Sql writer

getBuilder

public static org.apache.calcite.tools.RelBuilder getBuilder(DataSource dataSource,
                                                             String schemaName)
                                                      throws SQLException

Creates a RelBuilder with the given schema.

Parameters:

dataSource - The dataSource for the jdbc schema.

schemaName - The name of the schema used for the database.

Returns:

the relbuilder from Calcite.

Throws:

SQLException - if can't readSqlResultSet from database.