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## net.sourceforge.jtds.jdbc
Class CachedResultSet

    java.lang.Object
      |
      +--net.sourceforge.jtds.jdbc.JtdsResultSet
            |
            +--net.sourceforge.jtds.jdbc.CachedResultSet

All Implemented Interfaces:
  java.sql.ResultSet

public class CachedResultSet
extends JtdsResultSet

A memory cached scrollable/updateable result set.

Notes:

1. For maximum performance use the scroll insensitive result set type.
2. As the result set is cached in memory this implementation is limited to small result sets.
3. Updateable or scroll sensitive result sets are limited to selects which reference one table only.
4. Scroll sensitive result sets must have primary keys.
5. Updates are optimistic. To guard against lost updates it is recommended that the table includes a timestamp column.
6. This class is a plug-in replacement for the MSCursorResultSet class which may be advantageous in certain applications as the scroll insensitive result set implemented here is much faster than the server side cursor.
7. Updateable result sets cannot be built from the output of stored procedures.
8. This implementation uses 'select ... for browse' to obtain the column meta data needed to generate update statements etc.
9. Named forward updateable cursors are also supported in which case positioned updates and deletes are used referencing a server side declared cursor.
10. Named forward read only declared cursors can have a larger fetch size specified allowing a cursor alternative to the default direct select method.

Version:
  $Id: CachedResultSet.java,v 1.24 2005/09/21 21:50:34 ddkilzer Exp $
Author:
  Mike Hutchinson

Field Summary
`protected ConnectionJDBC2` | `connection` The parent connection object
`protected TdsCore` | `cursorTds` Cursor TdsCore object.
`protected int` | `initialRowCnt` The row count of the initial result set.
`protected ParamInfo[]` | `insertRow` Buffer row used for inserts.
`protected boolean` | `isKeyed` Table is keyed.
`protected boolean` | `isSybase` Flag to indicate Sybase.
`protected boolean` | `onInsertRow` Indicates currently inserting.
`protected ParamInfo[]` | `procedureParams` Original parameters.
`protected java.lang.String` | `procName` Original procedure name.
`protected boolean` | `rowDeleted` Indicates that row has been deleted.
`protected boolean` | `rowUpdated` Indicates that row has been updated.
`protected boolean` | `sizeChanged` Fetch size has been changed.
`protected java.lang.String` | `sql` Original SQL statement.
`protected java.lang.String` | `tableName` First table name in select.
`protected boolean` | `tempResultSet` True if this is a local temporary result set.
`protected ParamInfo[]` | `updateRow` The "update" row.
`protected TdsCore` | `updateTds` Updates TdsCore object used for positioned updates.

Fields inherited from class net.sourceforge.jtds.jdbc.JtdsResultSet
`cancelled, CLOSE_CURSORS_AT_COMMIT, closed, columnCount, columnMap, columns, concurrency, currentRow, cursorName, direction, f, fetchDirection, fetchSize, HOLD_CURSORS_OVER_COMMIT, INITIAL_ROW_COUNT, pos, POS_AFTER_LAST, POS_BEFORE_FIRST, resultSetType, rowData, rowPtr, rowsInResult, statement, wasNull`

Fields inherited from interface java.sql.ResultSet
`CONCUR_READ_ONLY, CONCUR_UPDATABLE, FETCH_FORWARD, FETCH_REVERSE, FETCH_UNKNOWN, TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE, TYPE_SCROLL_SENSITIVE`

Constructor Summary
`(package private)` | `CachedResultSet(JtdsResultSet rs, boolean load)` Creates a cached result set with the same columns (and optionally data) as an existing result set.
`(package private)` | `CachedResultSet(JtdsStatement statement, ColInfo[] columns, java.lang.Object[] data)` Creates a cached result set containing one row.
`(package private)` | `CachedResultSet(JtdsStatement statement, java.lang.String[] colName, int[] colType)` Constructs a cached result set based on locally generated data.
`(package private)` | `CachedResultSet(JtdsStatement statement, java.lang.String sql, java.lang.String procName, ParamInfo[] procedureParams, int resultSetType, int concurrency)` Constructs a new cached result set.

Method Summary
`boolean` | `absolute(int row)`
`void` | `afterLast()`
`void` | `beforeFirst()`
`protected static ParamInfo` | `buildParameter(int pos, ColInfo info, java.lang.Object value, boolean isUnicode)` Creates a parameter object for an UPDATE, DELETE or INSERT statement.
`(package private) ParamInfo[]` | `buildWhereClause(java.lang.StringBuffer sql, java.util.ArrayList params, boolean select)` Builds a WHERE clause for UPDATE or DELETE statements.
`void` | `cancelRowUpdates()`
`void` | `close()`
`private void` | `cursorClose()` Closes the result set.
`private void` | `cursorCreate()` Creates a new scrollable result set in memory or a named server cursor.
`private boolean` | `cursorFetch(int rowNum)` Fetches the next result row from the internal row array.
`void` | `deleteRow()`
`boolean` | `first()`
`java.lang.String` | `getCursorName()`
`void` | `insertRow()`
`(package private) boolean` | `isCursorUpdateable()` Analyses the tables in the result set and determines if the primary key columns needed to make it updateable exist.
`boolean` | `isLast()`
`boolean` | `last()`
`void` | `moveToCurrentRow()`
`void` | `moveToInsertRow()`
`boolean` | `next()`
`boolean` | `previous()`
`protected void` | `refreshKeyedRows()` Refreshes a result set row from keyed tables.
`protected void` | `refreshReRead()` Refreshes the row by rereading the result set.
`void` | `refreshRow()`
`boolean` | `relative(int row)`
`boolean` | `rowDeleted()`
`boolean` | `rowInserted()`
`boolean` | `rowUpdated()`
`protected java.lang.Object` | `setColValue(int colIndex, int jdbcType, java.lang.Object value, int length)` Sets the specified column's data value.
`(package private) void` | `setConcurrency(int concurrency)` Modify the concurrency of the result set.
`void` | `setFetchSize(int size)`
`void` | `updateRow()`

Methods inherited from class net.sourceforge.jtds.jdbc.JtdsResultSet
`cacheResultSetRows, checkOpen, checkScrollable, checkUpdateable, clearWarnings, copyInfo, copyRow, findColumn, getArray, getArray, getAsciiStream, getAsciiStream, getBigDecimal, getBigDecimal, getBigDecimal, getBigDecimal, getBinaryStream, getBinaryStream, getBlob, getBlob, getBoolean, getBoolean, getByte, getByte, getBytes, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getColumn, getColumnCount, getColumns, getConcurrency, getConnection, getCurrentRow, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getInt, getInt, getLong, getLong, getMetaData, getObject, getObject, getObject, getObject, getRef, getRef, getRow, getShort, getShort, getStatement, getString, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getURL, getURL, getWarnings, isAfterLast, isBeforeFirst, isFirst, newRow, notImplemented, setColLabel, setColName, setColType, setColumnCount, setFetchDirection, updateArray, updateArray, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBlob, updateBlob, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateClob, updateClob, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateRef, updateRef, updateShort, updateShort, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp, wasNull`

Methods inherited from class java.lang.Object
`, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait`

Field Detail

### onInsertRow

    protected boolean onInsertRow

  Indicates currently inserting.

### insertRow

    protected ParamInfo[] insertRow

  Buffer row used for inserts.

### updateRow

    protected ParamInfo[] updateRow

  The "update" row.

### rowUpdated

    protected boolean rowUpdated

  Indicates that row has been updated.

### rowDeleted

    protected boolean rowDeleted

  Indicates that row has been deleted.

### initialRowCnt

    protected int initialRowCnt

  The row count of the initial result set.

### tempResultSet

    protected final boolean tempResultSet

  True if this is a local temporary result set.

### cursorTds

    protected final TdsCore cursorTds

  Cursor TdsCore object.

### updateTds

    protected final TdsCore updateTds

  Updates TdsCore object used for positioned updates.

### isSybase

    protected boolean isSybase

  Flag to indicate Sybase.

### sizeChanged

    protected boolean sizeChanged

  Fetch size has been changed.

### sql

    protected java.lang.String sql

  Original SQL statement.

### procName

    protected final java.lang.String procName

  Original procedure name.

### procedureParams

    protected final ParamInfo[] procedureParams

  Original parameters.

### isKeyed

    protected boolean isKeyed

  Table is keyed.

### tableName

    protected java.lang.String tableName

  First table name in select.

### connection

    protected ConnectionJDBC2 connection

  The parent connection object

Constructor Detail

### CachedResultSet

    CachedResultSet(JtdsStatement statement,
                    java.lang.String sql,
                    java.lang.String procName,
                    ParamInfo[] procedureParams,
                    int resultSetType,
                    int concurrency)
              throws java.sql.SQLException

  Constructs a new cached result set.

  This result set will either be cached in memory or, if the cursor name is set, can be a forward only server side cursor. This latter form of cursor can also support positioned updates.
  Parameters:
    `statement` - the parent statement object
    `sql` - the SQL statement used to build the result set
    `procName` - an optional stored procedure name
    `procedureParams` - parameters for prepared statements
    `resultSetType` - the result set type eg scrollable
    `concurrency` - the result set concurrency eg updateable
  Throws:
    `java.sql.SQLException` - if an error occurs

### CachedResultSet

    CachedResultSet(JtdsStatement statement,
                    java.lang.String[] colName,
                    int[] colType)
              throws java.sql.SQLException

  Constructs a cached result set based on locally generated data.
  Parameters:
    `statement` - the parent statement object
    `colName` - array of column names
    `colType` - array of corresponding data types
  Throws:
    `java.sql.SQLException` - if an error occurs

### CachedResultSet

    CachedResultSet(JtdsResultSet rs,
                    boolean load)
              throws java.sql.SQLException

  Creates a cached result set with the same columns (and optionally data) as an existing result set.
  Parameters:
    `rs` - the result set to copy
    `load` - load data from the supplied result set
  Throws:
    `java.sql.SQLException` - if an error occurs

### CachedResultSet

    CachedResultSet(JtdsStatement statement,
                    ColInfo[] columns,
                    java.lang.Object[] data)
              throws java.sql.SQLException

  Creates a cached result set containing one row.
  Parameters:
    `statement` - the parent statement object
    `columns` - the column descriptor array
    `data` - the row data
  Throws:
    `java.sql.SQLException` - if an error occurs

Method Detail

### setConcurrency

    void setConcurrency(int concurrency)

  Modify the concurrency of the result set.

  Use to make result set read only once loaded.
  Parameters:
    `concurrency` - the concurrency value eg `ResultSet.CONCUR_READ_ONLY`

### cursorCreate

    private void cursorCreate()
                       throws java.sql.SQLException

  Creates a new scrollable result set in memory or a named server cursor.
  Throws:
    `java.sql.SQLException` - if an error occurs

### isCursorUpdateable

    boolean isCursorUpdateable()
                         throws java.sql.SQLException

  Analyses the tables in the result set and determines if the primary key columns needed to make it updateable exist.

  Sybase (and SQL 6.5) will automatically include any additional key and timestamp columns as hidden fields even if the user does not reference them in the select statement.

  If the table is unkeyed but there is an identity column then this is promoted to a key.

  Alternatively we can update, provided all the columns in the table row have been selected, by regarding all of them as keys.

  SQL Server 7+ does not return the correct primary key meta data for temporary tables so the driver has to query the catalog to locate any keys.
  Returns:
    `true`if there is one table and it is keyed``

### cursorFetch

    private boolean cursorFetch(int rowNum)
                         throws java.sql.SQLException

  Fetches the next result row from the internal row array.
  Parameters:
    `rowNum` - the row number to fetch
  Returns:
    `true` if a result set row is returned
  Throws:
    `java.sql.SQLException` - if an error occurs

### cursorClose

    private void cursorClose()
                      throws java.sql.SQLException

  Closes the result set.

### buildParameter

    protected static ParamInfo buildParameter(int pos,
                                              ColInfo info,
                                              java.lang.Object value,
                                              boolean isUnicode)
                                       throws java.sql.SQLException

  Creates a parameter object for an UPDATE, DELETE or INSERT statement.
  Parameters:
    `pos` - the substitution position of the parameter marker in the SQL
    `info` - the `ColInfo` column descriptor
    `value` - the column data item
  Returns:
    the new parameter as a `ParamInfo` object

### setColValue

    protected java.lang.Object setColValue(int colIndex,
                                           int jdbcType,
                                           java.lang.Object value,
                                           int length)
                                    throws java.sql.SQLException

  Sets the specified column's data value.
  Overrides:
    `setColValue` in class `JtdsResultSet`
  Parameters:
    `colIndex` - index of the column
    `value` - new column value
  Returns:
    the value, possibly converted to an internal type

### buildWhereClause

    ParamInfo[] buildWhereClause(java.lang.StringBuffer sql,
                                 java.util.ArrayList params,
                                 boolean select)
                           throws java.sql.SQLException

  Builds a WHERE clause for UPDATE or DELETE statements.
  Parameters:
    `sql` - the SQL Statement to append the WHERE clause to
    `params` - the parameter descriptor array for this statement
    `select` - true if this WHERE clause will be used in a select statement
  Returns:
    the parameter list as a `ParamInfo[]`
  Throws:
    `java.sql.SQLException` - if an error occurs

### refreshKeyedRows

    protected void refreshKeyedRows()
                             throws java.sql.SQLException

  Refreshes a result set row from keyed tables.

  If all the tables in the result set have primary keys then the result set row can be refreshed by refetching the individual table rows.
  Throws:
    `java.sql.SQLException` - if an error occurs

### refreshReRead

    protected void refreshReRead()
                          throws java.sql.SQLException

  Refreshes the row by rereading the result set.

  Obviously very slow on large result sets but may be the only option if tables do not have keys.

### setFetchSize

    public void setFetchSize(int size)
                      throws java.sql.SQLException

  Overrides:
    `setFetchSize` in class `JtdsResultSet`

### afterLast

    public void afterLast()
                   throws java.sql.SQLException

  Overrides:
    `afterLast` in class `JtdsResultSet`

### beforeFirst

    public void beforeFirst()
                     throws java.sql.SQLException

  Overrides:
    `beforeFirst` in class `JtdsResultSet`

### cancelRowUpdates

    public void cancelRowUpdates()
                          throws java.sql.SQLException

  Overrides:
    `cancelRowUpdates` in class `JtdsResultSet`

### close

    public void close()
               throws java.sql.SQLException

  Overrides:
    `close` in class `JtdsResultSet`

### deleteRow

    public void deleteRow()
                   throws java.sql.SQLException

  Overrides:
    `deleteRow` in class `JtdsResultSet`

### insertRow

    public void insertRow()
                   throws java.sql.SQLException

  Overrides:
    `insertRow` in class `JtdsResultSet`

### moveToCurrentRow

    public void moveToCurrentRow()
                          throws java.sql.SQLException

  Overrides:
    `moveToCurrentRow` in class `JtdsResultSet`

### moveToInsertRow

    public void moveToInsertRow()
                         throws java.sql.SQLException

  Overrides:
    `moveToInsertRow` in class `JtdsResultSet`

### refreshRow

    public void refreshRow()
                    throws java.sql.SQLException

  Overrides:
    `refreshRow` in class `JtdsResultSet`

### updateRow

    public void updateRow()
                   throws java.sql.SQLException

  Overrides:
    `updateRow` in class `JtdsResultSet`

### first

    public boolean first()
                  throws java.sql.SQLException

  Overrides:
    `first` in class `JtdsResultSet`

### isLast

    public boolean isLast()
                   throws java.sql.SQLException

  Overrides:
    `isLast` in class `JtdsResultSet`

### last

    public boolean last()
                 throws java.sql.SQLException

  Overrides:
    `last` in class `JtdsResultSet`

### next

    public boolean next()
                 throws java.sql.SQLException

  Overrides:
    `next` in class `JtdsResultSet`

### previous

    public boolean previous()
                     throws java.sql.SQLException

  Overrides:
    `previous` in class `JtdsResultSet`

### rowDeleted

    public boolean rowDeleted()
                       throws java.sql.SQLException

  Overrides:
    `rowDeleted` in class `JtdsResultSet`

### rowInserted

    public boolean rowInserted()
                        throws java.sql.SQLException

  Overrides:
    `rowInserted` in class `JtdsResultSet`

### rowUpdated

    public boolean rowUpdated()
                       throws java.sql.SQLException

  Overrides:
    `rowUpdated` in class `JtdsResultSet`

### absolute

    public boolean absolute(int row)
                     throws java.sql.SQLException

  Overrides:
    `absolute` in class `JtdsResultSet`

### relative

    public boolean relative(int row)
                     throws java.sql.SQLException

  Overrides:
    `relative` in class `JtdsResultSet`

### getCursorName

    public java.lang.String getCursorName()
                                   throws java.sql.SQLException

  Overrides:
    `getCursorName` in class `JtdsResultSet`

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Generated on November 8 2005