Mastering MySQL 4 [Electronic resources] نسخه متنی

ResultSet Methods

These methods require a valid ResultSet object, returned from the getResultSet() method.

absolute

resultset.absolute(int row)

Moves the cursor to the specified row from the result set (rows start at 1). You can use a negative number to move to a row starting from the end of the result set. Returns true if the cursor is on the row, false if not.

afterLast

resultset.afterlast()

Moves the cursor to the end of the result set.

beforeFirst

resultset.beforeFirst()

Moves the cursor to the start of the result set.

cancelRowUpdates

resultset.cancelRowUpdates()

Cancels updates made to the current row in the result set.

close

resultset.close()

Closes the result set and frees all associated resources.

deleteRow

resultset.deleteRow()

Deletes the current ResultSet row from the database (and the result set).

findColumn

resultset.findColumn(String field_name)

Maps the fieldname to the column in the result set and returns the column index as an integer.

first

resultset.first()

Moves the cursor to the first row in the result set. Returns true if there is a valid first row, false if not.

getXXX

resultset.getXXX(String fieldname | int fieldindex)

Returns the contents of a field of the specified type. You can identify the field by its name or its position.

Table F.3 shows the SQL types and their equivalent Java methods.

getCursorName

resultset.getCursorName()

Returns the name of the cursor used by the result set.

getFetchSize

resultset.getFetchSize()

Returns the fetch size for the result set object.

getMetaData

resultset.getMetaData()

Returns a ResultSetMetaData object with the number, type, and properties of the result set's columns.

getRow

resultset.getRow()

Returns an integer containing the current row number.

getStatement

resultset.getStatement()

Returns the statement object that created the result set.

getType

resultset.getType()

Returns the type of the result set object.

getWarnings

resultset.getWarnings()

Returns the first Warning triggered by a call from a ResultSet method on this result set.

insertRow

resultset.insertRow()

Inserts the contents of the insert row into the database (and the result set).

isAfterLast

resultet.isAfterLast()

Returns true if the cursor is after the last row in the result set, false if not.

isBeforeFirst

resultset.isBeforeFirst()

Returns true if the cursor is before the first row in the result set, false if not.

isFirst

resultset.isFirst()

Returns true if the cursor is at the first row in the result set, false if not.

isLast

resultset.isLast()

Returns true if the cursor is at the last row in the result set, false if not.

last

resultset.last()

Moves the cursor to the last row in the result set. Returns true if there is a valid last row, false if not.

moveToCurrentRow

resultset.moveToCurrentRow()

Moves the cursor to the remembered cursor position, which is usually the current row. This has no effect if the cursor is not on the insert row. See the moveToInsertRow() method.

moveToInsertRow

resultset.moveToInsertRow()

Moves the cursor to the insert row (a buffer where a new row can be placed with an update method). It remembers the current cursor position, which can be returned to with the moveToCurrentRow() method.

next

resultset.next()

Moves the cursor to the next row in the result set and returns true if there is a next row, false if there is not (the end has been reached).

For example:

connection = DriverManager.getConnection(url, "guru2b", "g00r002b");
statement = connection.createStatement();
resultset = statement.executeQuery("SELECT first_
name,surname FROM customer");
while(resultset.next()) {
String first_name = resultset.getString("first_name");
String surname = resultset.getString("surname");
System.out.print("Name: " + first_name + " " + surname);
}

previous

resultset.previous()

Moves the cursor to the previous row in the result set and returns true if there is a previous row, false if there is not (the start has been reached).

For example:

while(resultset.previous()) {
...
}

refreshRow

resultset.refreshRow()

Refreshes the current result set row with the most recent value in the database.

relative

resultset.relative(int rows)

Moves the cursor forward (if rows is positive) or backward (if rows is negative) by rows number of positions.

rowDeleted

resultset.rowDeleted()

Returns true if a row has been detected as deleted in the result set, false if not.

rowInserted

resultset.rowInserted()

Returns true if a row has been detected as inserted in the result set, false if not.

rowUpdated

resultset.rowUpdated()

Returns true if a row has been detected as updated in the result set, false if not.

setFetchSize

resultset.setFetchSize(int rows)

Gives the driver an idea of how many rows should be returned from the database when more rows are needed for the result set.

updateXXX

Updates the field with a value of the specified type. Table F.4 shows the SQL types and their equivalent Java methods.

updateRow

resultset.updateRow()

Updates the database with the contents of the current row of the result set.

wasNull

resultSet.wasNull()

Returns true if the previous field read was a SQL NULL, false if not.