Package weka.experiment

Class DatabaseUtils

java.lang.Object

weka.experiment.DatabaseUtils

All Implemented Interfaces:

Serializable, RevisionHandler

Direct Known Subclasses:

DatabaseConnection, DatabaseResultListener, DbUtils, InstanceQuery

public class DatabaseUtils
extends Object
implements Serializable, RevisionHandler

DatabaseUtils provides utility functions for accessing the experiment database. The jdbc driver and database to be used default to "jdbc.idbDriver" and "jdbc:idb=experiments.prp". These may be changed by creating a java properties file called DatabaseUtils.props in user.home or the current directory. eg:

 jdbcDriver=jdbc.idbDriver
 jdbcURL=jdbc:idb=experiments.prp
 

Version:

$Revision: 13476 $

Author:

Len Trigg (trigg@cs.waikato.ac.nz)

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BOOL	Type mapping for BOOL used for reading experiment results.
static final int	BYTE	Type mapping for BYTE used for reading experiment results.
static final int	DATE	Type mapping for DATE used for reading experiment results.
static final int	DOUBLE	Type mapping for DOUBLE used for reading experiment results.
static final String	EXP_INDEX_TABLE	The name of the table containing the index to experiments.
static final String	EXP_RESULT_COL	The name of the column containing the results table name.
static final String	EXP_RESULT_PREFIX	The prefix for result table names.
static final String	EXP_SETUP_COL	The name of the column containing the experiment setup (parameters).
static final String	EXP_TYPE_COL	The name of the column containing the experiment type (ResultProducer).
static final int	FLOAT	Type mapping for FLOAT used for reading experiment results.
static final int	INTEGER	Type mapping for INTEGER used for reading experiment results.
static final int	LONG	Type mapping for LONG used for reading experiment results.
static final String	PROPERTY_FILE	The name of the properties file.
static final int	SHORT	Type mapping for SHORT used for reading experiment results.
static final int	STRING	Type mapping for STRING used for reading experiment results.
static final int	TEXT	Type mapping for TEXT used for reading, e.g., text blobs.
static final int	TIME	Type mapping for TIME used for reading TIME columns.
static final int	TIMESTAMP	Type mapping for TIMESTAMP used for reading java.sql.Timestamp columns

Constructor Summary

Constructors

Constructor	Description
DatabaseUtils()	Reads properties and sets up the database drivers.
DatabaseUtils(File propsFile)	Reads the properties from the specified file and sets up the database drivers.
DatabaseUtils(Properties props)	Uses the specified properties to set up the database drivers.

Method Summary

Modifier and Type	Method	Description
static String	arrayToString(Object[] array)	Converts an array of objects to a string by inserting a space between each element.
String	attributeCaseFix(String columnName)	returns key column headings in their original case.
void	close()	closes the m_PreparedStatement to avoid memory leaks.
void	close(ResultSet rs)	closes the ResultSet and the statement that generated the ResultSet to avoid memory leaks in JDBC drivers - in contrast to the JDBC specs, a lot of JDBC drives don't clean up correctly.
void	connectToDatabase()	Opens a connection to the database.
void	createExperimentIndex()	Attempts to create the experiment index table.
String	createExperimentIndexEntry(ResultProducer rp)	Attempts to insert a results entry for the table into the experiment index.
String	createResultsTable(ResultProducer rp, String tableName)	Creates a results table for the supplied result producer.
String	databaseURLTipText()	Returns the tip text for this property.
String	debugTipText()	Returns the tip text for this property.
void	disconnectFromDatabase()	Closes the connection to the database.
boolean	execute(String query)	Executes a SQL query.
boolean	experimentIndexExists()	Returns true if the experiment index exists.
String	getDatabaseURL()	Get the value of DatabaseURL.
boolean	getDebug()	Gets whether there should be printed some debugging output to stderr or not.
String	getKeywords()	Returns the currently stored keywords (as comma-separated list).
String	getKeywordsMaskChar()	Returns the currently set mask character.
String	getPassword()	Get the database password.
Object[]	getResultFromTable(String tableName, ResultProducer rp, Object[] key)	Executes a database query to extract a result for the supplied key from the database.
ResultSet	getResultSet()	Gets the results generated by a previous query.
String	getResultsTableName(ResultProducer rp)	Gets the name of the experiment table that stores results from a particular ResultProducer.
String	getRevision()	Returns the revision string.
int	getSupportedCursorScrollType()	Returns the type of scrolling that the cursor supports, -1 if not supported or not connected.
String	getUsername()	Get the database username.
void	initialize(File propsFile)	Initializes the database connection.
void	initialize(Properties props)	Initializes the database connection.
boolean	isConnected()	Returns true if a database connection is active.
boolean	isCursorScrollable()	Checks whether cursors are scrollable in general, false otherwise (also if not connected).
boolean	isCursorScrollSensitive()	Returns whether the cursors only support forward movement or are scroll sensitive (with ResultSet.CONCUR_READ_ONLY concurrency).
boolean	isKeyword(String s)	Checks whether the given string is a reserved keyword.
String	maskKeyword(String s)	If the given string is a keyword, then the mask character will be appended and returned.
String	passwordTipText()	Returns the tip text for this property.
static String	processKeyString(String s)	processes the string in such a way that it can be stored in the database, i.e., it changes backslashes into slashes and doubles single quotes.
void	putResultInTable(String tableName, ResultProducer rp, Object[] key, Object[] result)	Executes a database query to insert a result for the supplied key into the database.
ResultSet	select(String query)	Executes a SQL SELECT query that returns a ResultSet.
void	setDatabaseURL(String newDatabaseURL)	Set the value of DatabaseURL.
void	setDebug(boolean d)	Sets whether there should be printed some debugging output to stderr or not.
void	setKeywords(String value)	Sets the keywords (comma-separated list) to use.
void	setKeywordsMaskChar(String value)	Sets the mask character to append to table or attribute names that are a reserved keyword.
void	setPassword(String password)	Set the database password.
void	setUsername(String username)	Set the database username.
boolean	tableExists(String tableName)	Checks that a given table exists.
int	translateDBColumnType(String type)	translates the column data type string to an integer value that indicates which data type / get()-Method to use in order to retrieve values from the database (see DatabaseUtils.Properties, InstanceQuery()).
static String	typeName(int type)	Returns the name associated with a SQL type.
int	update(String query)	Executes a SQL DDL query or an INSERT, DELETE or UPDATE.
String	usernameTipText()	Returns the tip text for this property.

Methods inherited from class java.lang.Object

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

Field Details

EXP_INDEX_TABLE

public static final String EXP_INDEX_TABLE

The name of the table containing the index to experiments.

See Also:

• Constant Field Values

EXP_TYPE_COL

public static final String EXP_TYPE_COL

The name of the column containing the experiment type (ResultProducer).

See Also:

• Constant Field Values

EXP_SETUP_COL

public static final String EXP_SETUP_COL

The name of the column containing the experiment setup (parameters).

See Also:

• Constant Field Values

EXP_RESULT_COL

public static final String EXP_RESULT_COL

The name of the column containing the results table name.

See Also:

• Constant Field Values

EXP_RESULT_PREFIX

public static final String EXP_RESULT_PREFIX

The prefix for result table names.

See Also:

• Constant Field Values

PROPERTY_FILE

public static final String PROPERTY_FILE

The name of the properties file.

See Also:

• Constant Field Values

STRING

public static final int STRING

Type mapping for STRING used for reading experiment results.

See Also:

• Constant Field Values

BOOL

public static final int BOOL

Type mapping for BOOL used for reading experiment results.

See Also:

• Constant Field Values

DOUBLE

public static final int DOUBLE

Type mapping for DOUBLE used for reading experiment results.

See Also:

• Constant Field Values

BYTE

public static final int BYTE

Type mapping for BYTE used for reading experiment results.

See Also:

• Constant Field Values

SHORT

public static final int SHORT

Type mapping for SHORT used for reading experiment results.

See Also:

• Constant Field Values

INTEGER

public static final int INTEGER

Type mapping for INTEGER used for reading experiment results.

See Also:

• Constant Field Values

LONG

public static final int LONG

Type mapping for LONG used for reading experiment results.

See Also:

• Constant Field Values

FLOAT

public static final int FLOAT

Type mapping for FLOAT used for reading experiment results.

See Also:

• Constant Field Values

DATE

public static final int DATE

Type mapping for DATE used for reading experiment results.

See Also:

• Constant Field Values

TEXT

public static final int TEXT

Type mapping for TEXT used for reading, e.g., text blobs.

See Also:

• Constant Field Values

TIME

public static final int TIME

Type mapping for TIME used for reading TIME columns.

See Also:

• Constant Field Values

TIMESTAMP

public static final int TIMESTAMP

Type mapping for TIMESTAMP used for reading java.sql.Timestamp columns

See Also:

• Constant Field Values

Constructor Details

DatabaseUtils

public DatabaseUtils()
              throws Exception

Reads properties and sets up the database drivers.

Throws:

Exception - if an error occurs

DatabaseUtils

public DatabaseUtils(File propsFile)
              throws Exception

Reads the properties from the specified file and sets up the database drivers.

Parameters:

propsFile - the props file to load, ignored if null or pointing to a directory

Throws:

Exception - if an error occurs

DatabaseUtils

public DatabaseUtils(Properties props)
              throws Exception

Uses the specified properties to set up the database drivers.

Parameters:

props - the properties to use, ignored if null

Throws:

Exception - if an error occurs

Method Details

initialize

public void initialize(File propsFile)

Initializes the database connection.

Parameters:

propsFile - the props file to load, ignored if null or pointing to a directory

initialize

public void initialize(Properties props)

Initializes the database connection.

Parameters:

props - the properties to obtain the parameters from, ignored if null

attributeCaseFix

public String attributeCaseFix(String columnName)

returns key column headings in their original case. Used for those databases that create uppercase column names.

Parameters:

columnName - the column to retrieve the original case for

Returns:

the original case

translateDBColumnType

public int translateDBColumnType(String type)

translates the column data type string to an integer value that indicates which data type / get()-Method to use in order to retrieve values from the database (see DatabaseUtils.Properties, InstanceQuery()). Blanks in the type are replaced with underscores "_", since Java property names can't contain blanks.

Parameters:

type - the column type as retrieved with java.sql.MetaData.getColumnTypeName(int)

Returns:

an integer value that indicates which data type / get()-Method to use in order to retrieve values from the

arrayToString

public static String arrayToString(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 String typeName(int type)

Returns the name associated with a SQL type.

Parameters:

type - the SQL type

Returns:

the name of the type

databaseURLTipText

public 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 String getDatabaseURL()

Get the value of DatabaseURL.

Returns:

Value of DatabaseURL.

setDatabaseURL

public void setDatabaseURL(String newDatabaseURL)

Set the value of DatabaseURL.

Parameters:

newDatabaseURL - Value to assign to DatabaseURL.

debugTipText

public String debugTipText()

Returns the tip text for this property.

Returns:

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

setDebug

public void setDebug(boolean d)

Sets whether there should be printed some debugging output to stderr or not.

Parameters:

d - true if output should be printed

getDebug

public boolean getDebug()

Gets whether there should be printed some debugging output to stderr or not.

Returns:

true if output should be printed

usernameTipText

public String usernameTipText()

Returns the tip text for this property.

Returns:

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

setUsername

public void setUsername(String username)

Set the database username.

Parameters:

username - Username for Database.

getUsername

public String getUsername()

Get the database username.

Returns:

Database username

passwordTipText

public String passwordTipText()

Returns the tip text for this property.

Returns:

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

setPassword

public void setPassword(String password)

Set the database password.

Parameters:

password - Password for Database.

getPassword

public String getPassword()

Get the database password.

Returns:

Password for Database.

connectToDatabase

public void connectToDatabase()
                       throws Exception

Opens a connection to the database.

Throws:

Exception - if an error occurs

disconnectFromDatabase

public void disconnectFromDatabase()
                            throws Exception

Closes the connection to the database.

Throws:

Exception - if an error occurs

isConnected

public boolean isConnected()

Returns true if a database connection is active.

Returns:

a value of type 'boolean'

isCursorScrollSensitive

public boolean isCursorScrollSensitive()

Returns whether the cursors only support forward movement or are scroll sensitive (with ResultSet.CONCUR_READ_ONLY concurrency). Returns always false if not connected

Returns:

true if connected and the cursor is scroll-sensitive

See Also:

• ResultSet.TYPE_SCROLL_SENSITIVE
• ResultSet.TYPE_FORWARD_ONLY
• ResultSet.CONCUR_READ_ONLY

isCursorScrollable

public boolean isCursorScrollable()

Checks whether cursors are scrollable in general, false otherwise (also if not connected).

Returns:

true if scrollable and connected

See Also:

• getSupportedCursorScrollType()

getSupportedCursorScrollType

public int getSupportedCursorScrollType()

Returns the type of scrolling that the cursor supports, -1 if not supported or not connected. Checks first for TYPE_SCROLL_SENSITIVE and then for TYPE_SCROLL_INSENSITIVE. In both cases CONCUR_READ_ONLY as concurrency is used.

Returns:

the scroll type, or -1 if not connected or no scrolling supported

See Also:

• ResultSet.TYPE_SCROLL_SENSITIVE
• ResultSet.TYPE_SCROLL_INSENSITIVE

execute

public boolean execute(String query)
                throws SQLException

Executes a SQL query. Caller must clean up manually with close().

Parameters:

query - the SQL query

Returns:

true if the query generated results

Throws:

SQLException - if an error occurs

See Also:

• close()

getResultSet

public ResultSet getResultSet()
                       throws SQLException

Gets the results generated by a previous query. Caller must clean up manually with close(ResultSet). Returns null if object has been deserialized.

Returns:

the result set.

Throws:

SQLException - if an error occurs

See Also:

• close(ResultSet)

update

public int update(String query)
           throws SQLException

Executes a SQL DDL query or an INSERT, DELETE or UPDATE.

Parameters:

query - the SQL DDL query

Returns:

the number of affected rows

Throws:

SQLException - if an error occurs

select

public ResultSet select(String query)
                 throws SQLException

Executes a SQL SELECT query that returns a ResultSet. Note: the ResultSet object must be closed by the caller.

Parameters:

query - the SQL query

Returns:

the generated ResultSet

Throws:

SQLException - if an error occurs

close

public void close(ResultSet rs)

closes the ResultSet and the statement that generated the ResultSet to avoid memory leaks in JDBC drivers - in contrast to the JDBC specs, a lot of JDBC drives don't clean up correctly.

Parameters:

rs - the ResultSet to clean up

close

public void close()

closes the m_PreparedStatement to avoid memory leaks.

tableExists

public boolean tableExists(String tableName)
                    throws Exception

Checks that a given table exists.

Parameters:

tableName - the name of the table to look for.

Returns:

true if the table exists.

Throws:

Exception - if an error occurs.

processKeyString

public static String processKeyString(String s)

processes the string in such a way that it can be stored in the database, i.e., it changes backslashes into slashes and doubles single quotes.

Parameters:

s - the string to work on

Returns:

the processed string

getResultFromTable

public Object[] getResultFromTable(String tableName,
 ResultProducer rp,
 Object[] key)
                            throws Exception

Executes a database query to extract a result for the supplied key from the database.

Parameters:

tableName - the name of the table where the result is stored

rp - the ResultProducer who will generate the result if required

key - the key for the result

Returns:

true if the result with that key is in the database already

Throws:

Exception - if an error occurs

putResultInTable

public void putResultInTable(String tableName,
 ResultProducer rp,
 Object[] key,
 Object[] result)
                      throws Exception

Executes a database query to insert a result for the supplied key into the database.

Parameters:

tableName - the name of the table where the result is stored

rp - the ResultProducer who will generate the result if required

key - the key for the result

result - the result to store

Throws:

Exception - if an error occurs

experimentIndexExists

public boolean experimentIndexExists()
                              throws Exception

Returns true if the experiment index exists.

Returns:

true if the index exists

Throws:

Exception - if an error occurs

createExperimentIndex

public void createExperimentIndex()
                           throws Exception

Attempts to create the experiment index table.

Throws:

Exception - if an error occurs.

createExperimentIndexEntry

public String createExperimentIndexEntry(ResultProducer rp)
                                  throws Exception

Attempts to insert a results entry for the table into the experiment index.

Parameters:

rp - the ResultProducer generating the results

Returns:

the name of the created results table

Throws:

Exception - if an error occurs.

getResultsTableName

public String getResultsTableName(ResultProducer rp)
                           throws Exception

Gets the name of the experiment table that stores results from a particular ResultProducer.

Parameters:

rp - the ResultProducer

Returns:

the name of the table where the results for this ResultProducer are stored, or null if there is no table for this ResultProducer.

Throws:

Exception - if an error occurs

createResultsTable

public String createResultsTable(ResultProducer rp,
 String tableName)
                          throws Exception

Creates a results table for the supplied result producer.

Parameters:

rp - the ResultProducer generating the results

tableName - the name of the resultsTable

Returns:

the name of the created results table

Throws:

Exception - if an error occurs.

setKeywords

public void setKeywords(String value)

Sets the keywords (comma-separated list) to use.

Parameters:

value - the list of keywords

getKeywords

public String getKeywords()

Returns the currently stored keywords (as comma-separated list).

Returns:

the list of keywords

setKeywordsMaskChar

public void setKeywordsMaskChar(String value)

Sets the mask character to append to table or attribute names that are a reserved keyword.

Parameters:

value - the new character

getKeywordsMaskChar

public String getKeywordsMaskChar()

Returns the currently set mask character.

Returns:

the character

isKeyword

public boolean isKeyword(String s)

Checks whether the given string is a reserved keyword.

Parameters:

s - the string to check

Returns:

true if the string is a keyword

See Also:

• m_Keywords

maskKeyword

public String maskKeyword(String s)

If the given string is a keyword, then the mask character will be appended and returned. Otherwise, the same string will be returned unchanged.

Parameters:

s - the string to check

Returns:

the potentially masked string

See Also:

• m_KeywordsMaskChar
• isKeyword(String)

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Returns:

the revision