org.apache.marmotta.kiwi.persistence

Class KiWiDialect

java.lang.Object

org.apache.marmotta.kiwi.persistence.KiWiDialect

Direct Known Subclasses:

H2Dialect, MySQLDialect, PostgreSQLDialect

public abstract class KiWiDialect
extends Object

A dialect provides the SQL statements necessary to access the different types of database systems. Each method should return a PreparedStatement that can be executed on the respective JDBC connection

Author: Sebastian Schaffert

Field Summary

Fields

Modifier and Type	Field and Description
static int	VERSION

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	KiWiDialect()

Method Summary

Methods

Modifier and Type	Method and Description
String	getCreateScript(String scriptName) Return the contents of the SQL create script used for initialising an empty database
abstract String	getDateTimeTZ(String alias) Return the SQL timezone value for a KiWiDateLiteral, corrected by the timezone offset.
abstract String	getDriverClass() Return the name of the driver class (used for properly initialising JDBC connections)
String	getDropScript(String scriptName) Return the contents of the SQL drop script used for cleaning up all traces of the KiWi triple store
abstract String	getGroupConcat(String value, String separator, boolean distinct) Return the name of the aggregate function for group concatenation (string_agg in postgres, GROUP_CONCAT in MySQL)
abstract String	getILike(String text, String pattern) Return the database specific case insensitive like comparison, e.g.
String	getMigrationScript(int oldVersion, String name) Return the contents of the SQL scripts used for migrating from the version given as argument to the current version.
abstract String	getRegexp(String text, String pattern, String flags) Return the database specific operator for matching a text against a regular expression.
protected String	getScript(String scriptName) Return the contents of the SQL script with the given file name (relative to the current class)
String	getStatement(String identifier) Return the SQL statement with the given identifier, or null if such a statement does not exist.
Set<String>	getStatementIdentifiers() Return all available statement identifiers.
abstract String	getValidationQuery() Get the query string that can be used for validating that a JDBC connection to this database is still valid.
int	getVersion()
boolean	hasStatement(String identifier) Return true if a statement with the given identifier exists
boolean	isArraySupported() Return true in case the database supports creating arrays with ARRAY[...]
abstract boolean	isBatchSupported() Return true if batched commits are supported by this dialect.
boolean	isCursorSupported() Return true in case the database system supports using cursors for queries over large data tables.
abstract boolean	isRegexpSupported(String flags) Return true in case the SPARQL RE flags contained in the given string are supported.

Methods inherited from class java.lang.Object

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

Field Detail

VERSION

public static final int VERSION

See Also:

Constant Field Values

Constructor Detail

KiWiDialect

protected KiWiDialect()
               throws DriverNotFoundException

Throws:

DriverNotFoundException

Method Detail

getVersion

public int getVersion()

getDriverClass

public abstract String getDriverClass()

Return the name of the driver class (used for properly initialising JDBC connections)

Returns:

isBatchSupported

public abstract boolean isBatchSupported()

Return true if batched commits are supported by this dialect.

Returns:

isArraySupported

public boolean isArraySupported()

Return true in case the database supports creating arrays with ARRAY[...]

Returns:

getCreateScript

public String getCreateScript(String scriptName)

Return the contents of the SQL create script used for initialising an empty database

Returns:

getDropScript

public String getDropScript(String scriptName)

Return the contents of the SQL drop script used for cleaning up all traces of the KiWi triple store

Returns:

getScript

protected String getScript(String scriptName)

Return the contents of the SQL script with the given file name (relative to the current class)

Returns:

getMigrationScript

public String getMigrationScript(int oldVersion,
                        String name)

Return the contents of the SQL scripts used for migrating from the version given as argument to the current version. In case the update covers several version steps, this method should concatenate the migration scripts in proper order.

Parameters:

oldVersion - the version to migrate the database from

name - name of the script to create; the method will look for scripts with name upgrade_name_oldv_newv.sql

Returns:

the migration script from the old version to the current version of the database schema, or null if the database is already the current version

getStatement

public String getStatement(String identifier)

Return the SQL statement with the given identifier, or null if such a statement does not exist. The statement identifiers are usually the keys in the statements.properties file for the respective database.

Parameters:

identifier - property key of the statement in statements.properties

Returns:

the SQL statement, or null if it does not exist

hasStatement

public boolean hasStatement(String identifier)

Return true if a statement with the given identifier exists

Parameters:

identifier - key of the statement to check

Returns:

true if a statement with the given identifier exists

getStatementIdentifiers

public Set<String> getStatementIdentifiers()

Return all available statement identifiers. The statement identifiers are usually the keys in the statements.properties file for the respective database.

Returns:

a set of all statement identifiers

getRegexp

public abstract String getRegexp(String text,
               String pattern,
               String flags)

Return the database specific operator for matching a text against a regular expression.

Parameters:

text -

pattern -

flags -

Returns:

isRegexpSupported

public abstract boolean isRegexpSupported(String flags)

Return true in case the SPARQL RE flags contained in the given string are supported.

Parameters:

flags -

Returns:

getILike

public abstract String getILike(String text,
              String pattern)

Return the database specific case insensitive like comparison, e.g. ILIKE in Postgres.

Parameters:

text -

pattern -

Returns:

getGroupConcat

public abstract String getGroupConcat(String value,
                    String separator,
                    boolean distinct)

Return the name of the aggregate function for group concatenation (string_agg in postgres, GROUP_CONCAT in MySQL)

Returns:

getDateTimeTZ

public abstract String getDateTimeTZ(String alias)

Return the SQL timezone value for a KiWiDateLiteral, corrected by the timezone offset. In PostgreSQL, this is e.g. computed by (ALIAS.tvalue + ALIAS.tzoffset * INTERVAL '1 second')

Parameters:

alias -

Returns:

getValidationQuery

public abstract String getValidationQuery()

Get the query string that can be used for validating that a JDBC connection to this database is still valid. Typically, this should be an inexpensive operation like "SELECT 1",

Returns:

isCursorSupported

public boolean isCursorSupported()

Return true in case the database system supports using cursors for queries over large data tables.

Returns: