mdbtools.dbengine

Class SelectEngine

java.lang.Object

mdbtools.dbengine.SelectEngine

public class SelectEngine
extends Object

SelectEngine is able to execute a select query TODO replace all runtime exceptions with sql exceptions

Field Summary

Fields

Modifier and Type	Field and Description
private Select	sql
private int[]	tableMap
private ArrayList	tasks

Constructor Summary

Constructors

Constructor and Description
SelectEngine(Select select)

Method Summary

Methods

Modifier and Type	Method and Description
private Data	aggregateQuery(Data data) execute an aggregate query
Data	execute()
private int	findTableIndex(Table t, Table[] tables)
private Task	fromClause()
private Data	getData() Resolve the from clause to a single set of data
private boolean	isAggregate() An aggregate query is true if any function is an aggregate function
private void	mergeData(MemoryData memData, Object[] _row, int columnIndex, RewindableData[] datas, int[] datasColumnCount, int dataIndex) merge the data from several datasets to a single dataset
private Data	nonAggregateQuery(Data data) non aggregate so simply return the column's wanted running any function requested
private Data	orderBy(Data data) sort the data todo: allow for sorting non-memory data
private Object	resolveColumn(Data data, Object column) resolve a column down to it's final value
private Data	where(MemoryData data, Object where) execute the where clause
private boolean	whereCheckRow(Data data, Object where) Check the where constraint against a single row
private boolean	whereCheckRowConditon(Data data, Condition condition) Check a condtion portion of the where constraint against a single row left and right of conditon is either another condition or an equation
private boolean	whereCheckRowEquation(Data data, Equation eq) Check an equation portion of the where contraints against a single row
private Task	whereClause(Task task)

Methods inherited from class java.lang.Object

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

Field Detail

sql

private Select sql

tableMap

private int[] tableMap

tasks

private ArrayList tasks

Constructor Detail

SelectEngine

public SelectEngine(Select select)

Method Detail

execute

public Data execute()
             throws SQLException

Throws:

SQLException

fromClause

private Task fromClause()

whereClause

private Task whereClause(Task task)

isAggregate

private boolean isAggregate()

An aggregate query is true if any function is an aggregate function

Returns:

booolean

aggregateQuery

private Data aggregateQuery(Data data)
                     throws SQLException

execute an aggregate query

Returns:

data

Throws:

SQLException

getData

private Data getData()
              throws SQLException

Resolve the from clause to a single set of data

Returns:

the data

Throws:

SQLException

findTableIndex

private int findTableIndex(Table t,
                 Table[] tables)

mergeData

private void mergeData(MemoryData memData,
             Object[] _row,
             int columnIndex,
             RewindableData[] datas,
             int[] datasColumnCount,
             int dataIndex)
                throws SQLException

merge the data from several datasets to a single dataset

Throws:

SQLException

nonAggregateQuery

private Data nonAggregateQuery(Data data)
                        throws SQLException

non aggregate so simply return the column's wanted running any function requested

Returns:

Data

Throws:

SQLException

resolveColumn

private Object resolveColumn(Data data,
                   Object column)
                      throws SQLException

resolve a column down to it's final value

Parameters:

data - the value from the data set

column - the object from the sql query

Returns:

Object

Throws:

SQLException

orderBy

private Data orderBy(Data data)

sort the data todo: allow for sorting non-memory data

Parameters:

data -

Returns:

Data

where

private Data where(MemoryData data,
         Object where)
            throws SQLException

execute the where clause

Throws:

SQLException

whereCheckRow

private boolean whereCheckRow(Data data,
                    Object where)
                       throws SQLException

Check the where constraint against a single row

Parameters:

data -

where -

Returns:

boolean

Throws:

SQLException

whereCheckRowEquation

private boolean whereCheckRowEquation(Data data,
                            Equation eq)
                               throws SQLException

Check an equation portion of the where contraints against a single row

Parameters:

data -

eq -

Returns:

boolean

Throws:

SQLException

whereCheckRowConditon

private boolean whereCheckRowConditon(Data data,
                            Condition condition)
                               throws SQLException

Check a condtion portion of the where constraint against a single row left and right of conditon is either another condition or an equation

Parameters:

data -

condition -

Returns:

boolean

Throws:

SQLException