ModSQL
Class SelectTable

java.lang.Object
  |
  +--ModSQL.SelectTable

All Implemented Interfaces:

DatabaseTable, DatabaseTableBase

class SelectTable

extends Object

implements DatabaseTable

Wrapper for a Select object to make it look like a DatabaseTable. This class is used when a SELECT statement appears as a subquery in the FROM section of some other SELECT statement.

Author:

chris.studholme@utoronto.ca

See Also:

Select

Field Summary

private boolean	afterlast Are we after the last row?
private boolean	beforefirst Are we before the first row?
private String	name Name of table.
private Table	query Query that generated the table.
private long	rownum Current row number.

Constructor Summary

SelectTable(Table query, String name)
Query should already be optimized before using this constructor.

Method Summary

boolean	absolute(Object id) Move to an absolute rowid in the table.
void	addColumn(String name, int type, int maxlen) Add a new column.
void	addRow() Add a new row.
void	afterLast() Set current row to after last row in table.
void	beforeFirst() Reset current row to before the first row in table.
void	close() Close the query.
void	commitUpdates() Commit column updates.
void	deleteRow() Delete current row.
protected void	finalize() Close table.
int	findColumn(String name) Find a column with the specified name.
int	getColumnCount() Number of columns in table.
int	getColumnDisplaySize(int column) Get maximum size of column.
String	getColumnLabel(int column) Get column label.
String	getColumnName(int column) Get name of column.
int	getColumnType(int column) Get column type.
Object	getObject(int column) Get the value of a column in the current row as a Java object.
long	getRowCount() Number of rows.
Object	getRowId() Returns the rowid for the current row.
String	getTableName() Name of table.
long	getTableSignature() Table signature.
long	getTableSize() Size of table in bytes.
boolean	isAfterLast() Are we after the last row?
boolean	isBeforeFirst() Are we before the first row?
boolean	isIndexAvailable(int column) Is an index available? Indices are not supported for tables generated from a query so this method just returns null.
boolean	isReadOnly() Is table readonly?
boolean	next() Advance to next row in table.
DatabaseIndex	openIndex(int column) Open an index on the table.
String	toString() Human readable description of table.
void	updateObject(int column, Object x) Update value of column.

Methods inherited from class java.lang.Object

, clone, equals, getClass, hashCode, notify, notifyAll, registerNatives, wait, wait, wait

Field Detail

query

private Table query

Query that generated the table.

name

private String name

Name of table.

beforefirst

private boolean beforefirst

Are we before the first row?

afterlast

private boolean afterlast

Are we after the last row?

rownum

private long rownum

Current row number.

Constructor Detail

SelectTable

public SelectTable(Table query,
                   String name)

Query should already be optimized before using this constructor.

Parameters:

query - optimized query to generate table

name - name of table

Method Detail

finalize

protected void finalize()

Close table. Just calls close() below.

Overrides:

finalize in class Object

close

public final void close()

Close the query.

Specified by:

close in interface DatabaseTableBase

Following copied from interface: ModSQL.DatabaseTableBase

Throws:

DatabaseException - if a database-access error occurs

openIndex

public DatabaseIndex openIndex(int column)

Open an index on the table. Indices are not supported for tables generated from a query so this method just returns null.

Specified by:

openIndex in interface DatabaseTable

Parameters:

column - open index for desired column

Returns:

null

isIndexAvailable

public boolean isIndexAvailable(int column)

Is an index available? Indices are not supported for tables generated from a query so this method just returns null.

Specified by:

isIndexAvailable in interface DatabaseTable

Parameters:

column - desired index

Returns:

false

isReadOnly

public boolean isReadOnly()

Is table readonly?

Specified by:

isReadOnly in interface DatabaseTable

Returns:

true

getTableSize

public long getTableSize()

Size of table in bytes.

Specified by:

getTableSize in interface DatabaseTable

Returns:

-1 (unknown)

getTableSignature

public long getTableSignature()

Table signature.

Specified by:

getTableSignature in interface DatabaseTable

Returns:

0

getTableName

public String getTableName()

Name of table.

Specified by:

getTableName in interface DatabaseTable

Returns:

table name

getColumnCount

public int getColumnCount()
                   throws DatabaseException

Number of columns in table.

Specified by:

getColumnCount in interface DatabaseTable

Returns:

number of columns

Throws:

DatabaseException - is the query fails

getRowCount

public long getRowCount()

Number of rows.

Specified by:

getRowCount in interface DatabaseTableBase

Returns:

-1 (unknown)

toString

public String toString()

Human readable description of table.

Overrides:

toString in class Object

Returns:

the query

findColumn

public int findColumn(String name)
               throws DatabaseException

Find a column with the specified name.

Specified by:

findColumn in interface DatabaseTable

Parameters:

name - name of column to find

Returns:

index of column (-1 if not found)

Throws:

DatabaseException - if there is a problem with the query

getColumnName

public String getColumnName(int column)
                     throws DatabaseException

Get name of column.

Specified by:

getColumnName in interface DatabaseTable

Parameters:

column - index of column

Returns:

name of column

Throws:

DatabaseException - if there is a problem with the query

getColumnLabel

public String getColumnLabel(int column)
                      throws DatabaseException

Get column label. This method is the same as getColumnName() above.

Specified by:

getColumnLabel in interface DatabaseTable

Parameters:

column - index of column

Returns:

label for column

Throws:

DatabaseException - if there is a problem with the query

getColumnType

public int getColumnType(int column)
                  throws DatabaseException

Get column type.

Specified by:

getColumnType in interface DatabaseTable

Parameters:

column - index of column

Returns:

SQL type of column

Throws:

DatabaseException - if there is a problem with the query

getColumnDisplaySize

public int getColumnDisplaySize(int column)
                         throws DatabaseException

Get maximum size of column.

Specified by:

getColumnDisplaySize in interface DatabaseTable

Parameters:

column - index of column

Returns:

maximum size of column in characters

Throws:

DatabaseException - if there is a problem with the query

addColumn

public void addColumn(String name,
                      int type,
                      int maxlen)
               throws DatabaseException

Add a new column.

Specified by:

addColumn in interface DatabaseTable

Throws:

DatabaseException - always since table is read-only

next

public boolean next()
             throws DatabaseException

Advance to next row in table.

Specified by:

next in interface DatabaseTableBase

Returns:

true if a valid row was found

Throws:

DatabaseException - if there is a problem with the query

deleteRow

public void deleteRow()
               throws DatabaseException

Delete current row.

Specified by:

deleteRow in interface DatabaseTableBase

Throws:

DatabaseException - always since table is read-only

addRow

public void addRow()
            throws DatabaseException

Add a new row.

Specified by:

addRow in interface DatabaseTable

Throws:

DatabaseException - always since table is read-only

isBeforeFirst

public boolean isBeforeFirst()

Are we before the first row?

Specified by:

isBeforeFirst in interface DatabaseTableBase

Returns:

true if table is before the first row

isAfterLast

public boolean isAfterLast()

Are we after the last row?

Specified by:

isAfterLast in interface DatabaseTableBase

Returns:

true if table is after the last row

beforeFirst

public void beforeFirst()
                 throws DatabaseException

Reset current row to before the first row in table.

Specified by:

beforeFirst in interface DatabaseTableBase

Throws:

DatabaseException - if there is a problem with the query

afterLast

public void afterLast()

Set current row to after last row in table.

Specified by:

afterLast in interface DatabaseTableBase

Following copied from interface: ModSQL.DatabaseTableBase

Throws:

DatabaseException - if a database-access error occurs

getRowId

public Object getRowId()

Returns the rowid for the current row.

Specified by:

getRowId in interface DatabaseTableBase

Returns:

rowid object

absolute

public boolean absolute(Object id)
                 throws DatabaseException

Move to an absolute rowid in the table.

Specified by:

absolute in interface DatabaseTable

Parameters:

rowid - id of row to seek

Returns:

true if row was found, false otherwise

Throws:

DatabaseException - always since this method is not supported

getObject

public Object getObject(int column)
                 throws DatabaseException

Get the value of a column in the current row as a Java object.

Specified by:

getObject in interface DatabaseTableBase

Parameters:

column - index of column

Returns:

an Object holding the column value

Throws:

DatabaseException - if there is a problem with the query

updateObject

public void updateObject(int column,
                         Object x)
                  throws DatabaseException

Update value of column.

Specified by:

updateObject in interface DatabaseTableBase

Parameters:

column - index of column to update

x - new column value

Throws:

DatabaseException - always since table is read-only

commitUpdates

public void commitUpdates()
                   throws DatabaseException

Commit column updates.

Specified by:

commitUpdates in interface DatabaseTableBase

Throws:

DatabaseException - always since table is read-only