weka.core.converters
Class DatabaseConnection

java.lang.Object
  weka.core.converters.DatabaseConnection

All Implemented Interfaces:

java.io.Serializable

public class DatabaseConnection

extends java.lang.Object

implements java.io.Serializable

Connects to a database.

Version:

$Revision: 1.1 $

Author:

Len Trigg (trigg@cs.waikato.ac.nz), Stefan Mutter (mutter@cs.waikato.ac.nz)

See Also:

Serialized Form

Field Summary

static int	BOOL
static int	BYTE
static int	DATE
static int	DOUBLE
static int	FLOAT
static int	INTEGER
static int	LONG
static int	SHORT
static int	STRING

Constructor Summary

DatabaseConnection()
Sets up the database drivers

Method Summary

static java.lang.String	arrayToString(java.lang.Object[] array) Converts an array of objects to a string by inserting a space between each element.
void	connectToDatabase() Opens a connection to the database
java.lang.String	databaseURLTipText() Returns the tip text for this property
void	disconnectFromDatabase() Closes the connection to the database.
boolean	execute(java.lang.String query) Executes a SQL query.
java.lang.String	getDatabaseURL() Get the value of DatabaseURL.
java.sql.DatabaseMetaData	getMetaData() Gets meta data for the database connection object.
java.lang.String	getPassword() Get the database password
java.sql.ResultSet	getResultSet() Gets the results generated by a previous query.
int	getUpdateCount() Dewtermines if the current query retrieves a result set or updates a table
boolean	getUpperCase() Check if the property checkUpperCaseNames in the DatabaseUtils file is set to true or false.
java.lang.String	getUsername() Get the database username
boolean	isConnected() Returns true if a database connection is active.
void	setDatabaseURL(java.lang.String newDatabaseURL) Set the value of DatabaseURL.
void	setPassword(java.lang.String password) Set the database password
void	setUsername(java.lang.String username) Set the database username
boolean	tableExists(java.lang.String tableName) Checks that a given table exists.
static java.lang.String	typeName(int type) Returns the name associated with a SQL type.

Methods inherited from class java.lang.Object

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

Field Detail

STRING

public static final int STRING

See Also:

Constant Field Values

BOOL

public static final int BOOL

See Also:

Constant Field Values

DOUBLE

public static final int DOUBLE

See Also:

Constant Field Values

BYTE

public static final int BYTE

See Also:

Constant Field Values

SHORT

public static final int SHORT

See Also:

Constant Field Values

INTEGER

public static final int INTEGER

See Also:

Constant Field Values

LONG

public static final int LONG

See Also:

Constant Field Values

FLOAT

public static final int FLOAT

See Also:

Constant Field Values

DATE

public static final int DATE

See Also:

Constant Field Values

Constructor Detail

DatabaseConnection

public DatabaseConnection()
                   throws java.lang.Exception

Sets up the database drivers

Throws:

java.lang.Exception - if an error occurs

Method Detail

setUsername

public void setUsername(java.lang.String username)

Set the database username

Parameters:

username - Username for Database.

getUsername

public java.lang.String getUsername()

Get the database username

Returns:

Database username

setPassword

public void setPassword(java.lang.String password)

Set the database password

Parameters:

password - Password for Database.

getPassword

public java.lang.String getPassword()

Get the database password

Returns:

Password for Database.

databaseURLTipText

public java.lang.String databaseURLTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

getDatabaseURL

public java.lang.String getDatabaseURL()

Get the value of DatabaseURL.

Returns:

Value of DatabaseURL.

setDatabaseURL

public void setDatabaseURL(java.lang.String newDatabaseURL)

Set the value of DatabaseURL.

Parameters:

newDatabaseURL - Value to assign to DatabaseURL.

getUpperCase

public boolean getUpperCase()

Check if the property checkUpperCaseNames in the DatabaseUtils file is set to true or false.

Returns:

true if the property checkUpperCaseNames in the DatabaseUtils file is set to true, false otherwise.

arrayToString

public static java.lang.String arrayToString(java.lang.Object[] array)

Converts an array of objects to a string by inserting a space between each element. Null elements are printed as ?

Parameters:

array - the array of objects

Returns:

a value of type 'String'

typeName

public static java.lang.String typeName(int type)

Returns the name associated with a SQL type.

Parameters:

type - the SQL type

Returns:

the name of the type

connectToDatabase

public void connectToDatabase()
                       throws java.lang.Exception

Opens a connection to the database

Throws:

java.lang.Exception - if an error occurs

disconnectFromDatabase

public void disconnectFromDatabase()
                            throws java.lang.Exception

Closes the connection to the database.

Throws:

java.lang.Exception - if an error occurs

getMetaData

public java.sql.DatabaseMetaData getMetaData()
                                      throws java.lang.Exception

Gets meta data for the database connection object.

Returns:

the meta data.

Throws:

java.sql.SQLException - if an error occurs

java.lang.Exception

isConnected

public boolean isConnected()

Returns true if a database connection is active.

Returns:

a value of type 'boolean'

execute

public boolean execute(java.lang.String query)
                throws java.sql.SQLException

Executes a SQL query.

Parameters:

query - the SQL query

Returns:

true if the query generated results

Throws:

java.sql.SQLException - if an error occurs

getResultSet

public java.sql.ResultSet getResultSet()
                                throws java.sql.SQLException

Gets the results generated by a previous query.

Returns:

the result set.

Throws:

java.sql.SQLException - if an error occurs

getUpdateCount

public int getUpdateCount()
                   throws java.sql.SQLException

Dewtermines if the current query retrieves a result set or updates a table

Returns:

the update count (-1 if the query retrieves a result set).

Throws:

java.sql.SQLException - if an error occurs

tableExists

public boolean tableExists(java.lang.String tableName)
                    throws java.lang.Exception

Checks that a given table exists.

Parameters:

tableName - the name of the table to look for.

Returns:

true if the table exists.

Throws:

java.lang.Exception - if an error occurs.