edu.udo.cs.miningmart.db
Class DbCorePostgres

java.lang.Object
  edu.udo.cs.miningmart.db.DbCore
      edu.udo.cs.miningmart.db.DbCorePostgres

public class DbCorePostgres

extends DbCore

This class provides an access to a PostgreSQL DBMS. It has only been tested with PostgreSQL version 7.3.2. See www.postgresgl.org and jdbc.postgresql.org. Please note that for using PostgreSQL, the db.config file must have a slightly different format: the line that contains the database server name and the port must begin with "//" instead of "@" and must not be ended by a colon. To compile this class, the PostgreSQL JDBC driver package must be added to the classpath.

Version:

$Id: DbCorePostgres.java,v 1.9 2006/05/22 20:11:52 euler Exp $

Author:

Timm Euler

Field Summary

static java.lang.String	POSTGRES_TYPE_CHAR The public constant indicating the Postgres Datatype CHAR
static java.lang.String	POSTGRES_TYPE_DATE The public constant indicating the Postgres Datatype DATE
static java.lang.String	POSTGRES_TYPE_NUMBER The public constant indicating the Postgres Datatype NUMERIC
static java.lang.String	POSTGRES_TYPE_STRING The public constant indicating the Postgres Datatype VARCHAR
static java.lang.String	POSTGRES_TYPE_TEXT The public constant indicating the Postgres Datatype TEXT
static java.lang.String	POSTGRES_TYPE_TIME The public constant indicating the Postgres Datatype TIME
static java.lang.String	POSTGRES_TYPE_TIMESTAMP The public constant indicating the Postgres Datatype TIMESTAMP

Fields inherited from class edu.udo.cs.miningmart.db.DbCore

DBMS_ORACLE, DBMS_POSTGRES

Constructor Summary

DbCorePostgres(java.lang.String url, java.lang.String dbName, java.lang.String user, java.lang.String passwd, M4InterfaceContext cal, boolean isM4Schema)
The constructor of this class calls the constructor of the superclass DbCore.

Method Summary

void	commitTransactions() Commit the last transactions in the M4 database.
boolean	dropRelation(java.lang.String tableName) Try to drop the table or view with the given name, if it exists.
java.lang.String	getAttributeForColumnNames() Abstract method to be implemented by the subclasses.
java.lang.String	getAttributeForColumnTypes() Abstract method to be implemented by the subclasses.
java.lang.String	getDatatypeName(java.lang.String m4RelDatatypeName, int size) This method returns the DBMS-dependent name of the datatype which the current DBMS uses to realize the given M4-Relational Datatype.
short	getDbms() Indicates the DBMS used.
java.lang.String	getM4DatatypeName(java.lang.String dbmsDatatypeName) This method returns the M4-Relational Datatype that corresponds to the given DBMS-dependent name of a datatype.
protected long	getNextM4SequenceValue(java.sql.Statement stmt)
java.util.Collection	getPrimaryKeyColumnNames(java.lang.String dbObjectName) Returns a Collection with the names of the DB columns that belong to the given table or view and form its primary key, if such a key is declared by SQL constraints in the DB.
java.lang.String	getSelectStringAllColumnsForDbObject(java.lang.String dbObjectName) Abstract method to be implemented by the subclasses.
java.lang.String	getSelectStringAllTables() Abstract method to be implemented by the subclasses.
java.lang.String	getSelectStringAllViews() Abstract method to be implemented by the subclasses.
java.lang.String	getSelectStringColumnDataTypes(java.lang.String dbObjectName, java.lang.String owner, java.lang.String columnName) This method returns the DBMS-dependent SQL command that returns the name of the datatype of the given column in the given table or view (which is owned by the given owner).
java.lang.String	getTableOrViewType(java.lang.String dbObjectName) Returns one of the TYPE_... constants in the class edu.udo.cs.miningmart.m4.Columnset, or null if the given String is neither a table or view.
java.util.Map	getTablesReferencedBy(java.lang.String dbObjectName) Returns a Map that maps every column of the given table to the name of the table that it references as a foreign key, or to null if the column does not act as a foreign key.
java.lang.String	getTestQuery()
java.lang.String	getUniqueRowIdentifier() WARNING: the unique row identifier works only for tables in Postgres!
boolean	isColumnUsedAsPrimaryKey(java.lang.String columnName, java.lang.String dbObjectName)
protected void	registerJDBC_Driver() Implements the superclass method so that the correct JDBC driver for PostgreSQL is used.
protected void	switchAutocommitOff(java.sql.Connection con) Since the transaction mechanism may be different for different DBMS, use this method to implement the Autocommit handling.
boolean	tableExists(java.lang.String tableName) Returns TRUE if a table (not a view) with the given name exists in the database.

Methods inherited from class edu.udo.cs.miningmart.db.DbCore

createSQLFunction, createSqlIndex, createSQLView, executeDBProcedure, executeSingleValueSqlRead, executeSingleValueSqlReadL, executeSingleValueSqlReadL, executeSqlRead, executeSqlWrite, finalize, findDBMS, getCasePrintObject, hasOnlyForeignKeyColumns, rollback

Methods inherited from class java.lang.Object

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

Field Detail

POSTGRES_TYPE_NUMBER

public static final java.lang.String POSTGRES_TYPE_NUMBER

The public constant indicating the Postgres Datatype NUMERIC

See Also:

Constant Field Values

POSTGRES_TYPE_STRING

public static final java.lang.String POSTGRES_TYPE_STRING

The public constant indicating the Postgres Datatype VARCHAR

See Also:

Constant Field Values

POSTGRES_TYPE_CHAR

public static final java.lang.String POSTGRES_TYPE_CHAR

The public constant indicating the Postgres Datatype CHAR

See Also:

Constant Field Values

POSTGRES_TYPE_DATE

public static final java.lang.String POSTGRES_TYPE_DATE

The public constant indicating the Postgres Datatype DATE

See Also:

Constant Field Values

POSTGRES_TYPE_TIME

public static final java.lang.String POSTGRES_TYPE_TIME

The public constant indicating the Postgres Datatype TIME

See Also:

Constant Field Values

POSTGRES_TYPE_TIMESTAMP

public static final java.lang.String POSTGRES_TYPE_TIMESTAMP

The public constant indicating the Postgres Datatype TIMESTAMP

See Also:

Constant Field Values

POSTGRES_TYPE_TEXT

public static final java.lang.String POSTGRES_TYPE_TEXT

The public constant indicating the Postgres Datatype TEXT

See Also:

Constant Field Values

Constructor Detail

DbCorePostgres

public DbCorePostgres(java.lang.String url,
                      java.lang.String dbName,
                      java.lang.String user,
                      java.lang.String passwd,
                      M4InterfaceContext cal,
                      boolean isM4Schema)
               throws java.sql.SQLException

The constructor of this class calls the constructor of the superclass DbCore. Autocommit is set to false, so transaction management must be done individually by the database functions.

Parameters:

url - Prefix of the database url

dbName - name of the database

user - name of the database user

passwd - password for the database user

cal - the CompilerAccessLogic of the current thread. It is just needed in order to reach the appropriate Print-object for writing debug messages

isM4Schema - is true iff the connection refers to the M4 schema. Useful to decide whether triggers need to be switched off etc.

Throws:

java.sql.SQLException

See Also:

edu.udo.cs.miningmart.m4.core.utils.DbCore#DbCore(String, String, String, String, CompilerAccessLogic, boolean)

Method Detail

registerJDBC_Driver

protected void registerJDBC_Driver()
                            throws java.sql.SQLException

Implements the superclass method so that the correct JDBC driver for PostgreSQL is used.

Specified by:

registerJDBC_Driver in class DbCore

Throws:

java.sql.SQLException

getDbms

public short getDbms()

Indicates the DBMS used.

Specified by:

getDbms in class DbCore

Returns:

The public static constant DB.POSTGRES

switchAutocommitOff

protected void switchAutocommitOff(java.sql.Connection con)
                            throws java.sql.SQLException

Description copied from class: DbCore

Since the transaction mechanism may be different for different DBMS, use this method to implement the Autocommit handling.

Specified by:

switchAutocommitOff in class DbCore

Throws:

java.sql.SQLException

See Also:

DbCore#switchAutocommitOff()

commitTransactions

public void commitTransactions()
                        throws java.sql.SQLException

Commit the last transactions in the M4 database. This method overrides the superclass method because POSTGRES uses a slightly modified transaction mechanism.

Overrides:

commitTransactions in class DbCore

Throws:

java.sql.SQLException

getNextM4SequenceValue

protected long getNextM4SequenceValue(java.sql.Statement stmt)
                               throws M4Exception

Specified by:

getNextM4SequenceValue in class DbCore

Parameters:

stmt - the Statement to be used to execute the query

Returns:

the value returned by the sequence (installed in the M4 schema).

Throws:

M4Exception - if for some reason the sequence does not return a value

See Also:

DbCore.getNextM4SequenceValue(Statement)

getSelectStringAllTables

public java.lang.String getSelectStringAllTables()

Description copied from class: DbCore

Abstract method to be implemented by the subclasses. Returns an SQL String that selects the names of all tables from the current schema. This is DBMS-dependent.

Specified by:

getSelectStringAllTables in class DbCore

Returns:

An SQL String

See Also:

DbCore

getSelectStringAllViews

public java.lang.String getSelectStringAllViews()

Description copied from class: DbCore

Abstract method to be implemented by the subclasses. Returns an SQL String that selects the names of all views from the current schema. This is DBMS-dependent.

Specified by:

getSelectStringAllViews in class DbCore

Returns:

An SQL String

See Also:

DbCore

getSelectStringAllColumnsForDbObject

public java.lang.String getSelectStringAllColumnsForDbObject(java.lang.String dbObjectName)

Description copied from class: DbCore

Abstract method to be implemented by the subclasses. Returns the SQL String that selects all column names and types for the given Table or View name from the business data schema. This is DBMS-dependent.

Specified by:

getSelectStringAllColumnsForDbObject in class DbCore

Parameters:

dbObjectName - Name of a table OR view in the business data schema

Returns:

An SQL String

See Also:

DbCore

tableExists

public boolean tableExists(java.lang.String tableName)
                    throws M4Exception

Description copied from class: DbCore

Returns TRUE if a table (not a view) with the given name exists in the database.

Specified by:

tableExists in class DbCore

Parameters:

tableName - the table name

Returns:

TRUE or FALSE

Throws:

M4Exception

getSelectStringColumnDataTypes

public java.lang.String getSelectStringColumnDataTypes(java.lang.String dbObjectName,
                                                       java.lang.String owner,
                                                       java.lang.String columnName)

Description copied from class: DbCore

This method returns the DBMS-dependent SQL command that returns the name of the datatype of the given column in the given table or view (which is owned by the given owner).

Specified by:

getSelectStringColumnDataTypes in class DbCore

Parameters:

dbObjectName - Name of a table or view in the business data schema

owner - Name of the owner of the table or view (can be null)

columnName - Name of the column whose datatype is returned

Returns:

the DBMS-dependent name of the datatype of the column with the given name

See Also:

DbCore

getPrimaryKeyColumnNames

public java.util.Collection getPrimaryKeyColumnNames(java.lang.String dbObjectName)
                                              throws java.sql.SQLException,
                                                     DbConnectionClosed

Description copied from class: DbCore

Returns a Collection with the names of the DB columns that belong to the given table or view and form its primary key, if such a key is declared by SQL constraints in the DB. Otherwise null is returned.

Specified by:

getPrimaryKeyColumnNames in class DbCore

Parameters:

dbObjectName - the name of the given table or view

Returns:

a Collection of Strings

Throws:

java.sql.SQLException

DbConnectionClosed

See Also:

DbCore

isColumnUsedAsPrimaryKey

public boolean isColumnUsedAsPrimaryKey(java.lang.String columnName,
                                        java.lang.String dbObjectName)
                                 throws java.sql.SQLException,
                                        DbConnectionClosed

Throws:

java.sql.SQLException

DbConnectionClosed

getTablesReferencedBy

public java.util.Map getTablesReferencedBy(java.lang.String dbObjectName)
                                    throws java.sql.SQLException,
                                           DbConnectionClosed

Description copied from class: DbCore

Returns a Map that maps every column of the given table to the name of the table that it references as a foreign key, or to null if the column does not act as a foreign key. The Map uses only Strings.

Specified by:

getTablesReferencedBy in class DbCore

Parameters:

dbObjectName - the given table name

Returns:

a Map whose keys and values are Strings

Throws:

java.sql.SQLException

DbConnectionClosed

See Also:

DbCore

getTableOrViewType

public java.lang.String getTableOrViewType(java.lang.String dbObjectName)
                                    throws java.sql.SQLException,
                                           DbConnectionClosed

Returns one of the TYPE_... constants in the class edu.udo.cs.miningmart.m4.Columnset, or null if the given String is neither a table or view.

Specified by:

getTableOrViewType in class DbCore

Parameters:

dbObjectName - name of a table or view

Returns:

a String with the type information

Throws:

java.sql.SQLException

DbConnectionClosed

getAttributeForColumnNames

public java.lang.String getAttributeForColumnNames()

Description copied from class: DbCore

Abstract method to be implemented by the subclasses. Returns the name of the column that contains the column names. This is DBMS-dependent.

Specified by:

getAttributeForColumnNames in class DbCore

Returns:

the name of the column that contains the column names

See Also:

DbCore

getAttributeForColumnTypes

public java.lang.String getAttributeForColumnTypes()

Description copied from class: DbCore

Abstract method to be implemented by the subclasses. Returns the name of the column that contains the column types. This is DBMS-dependent.

Specified by:

getAttributeForColumnTypes in class DbCore

Returns:

the name of the column that contains the column types

See Also:

DbCore

getUniqueRowIdentifier

public java.lang.String getUniqueRowIdentifier()

WARNING: the unique row identifier works only for tables in Postgres!

Specified by:

getUniqueRowIdentifier in class DbCore

Returns:

the unique row identifier name

See Also:

DbCore

getDatatypeName

public java.lang.String getDatatypeName(java.lang.String m4RelDatatypeName,
                                        int size)

Description copied from class: DbCore

This method returns the DBMS-dependent name of the datatype which the current DBMS uses to realize the given M4-Relational Datatype.

Specified by:

getDatatypeName in class DbCore

Parameters:

m4RelDatatypeName - name of the M4 Relational Datatype

size - A size to be returned with the datatype, if the DBMS allows that. For example, if the M4 Relational Datatype is NUMBER and length is 10, then the return value will be the String "NUMBER(10)" if the DBMS is Oracle. If this length is not positive, the datatype will be returned without a size, in the example: "NUMBER". The DBMS may not allow lengths at all, in which case also the datatype without a size is returned.

Returns:

A DBMS-dependent string that contains a datatype name.

See Also:

DbCore

getM4DatatypeName

public java.lang.String getM4DatatypeName(java.lang.String dbmsDatatypeName)

Description copied from class: DbCore

This method returns the M4-Relational Datatype that corresponds to the given DBMS-dependent name of a datatype.

Specified by:

getM4DatatypeName in class DbCore

Parameters:

dbmsDatatypeName - the name of the datatype in the underlying DBMS

Returns:

the corresponding M4 Relational Datatype

See Also:

DbCore

dropRelation

public boolean dropRelation(java.lang.String tableName)
                     throws M4Exception

Try to drop the table or view with the given name, if it exists. Returns TRUE iff the table had existed, FALSE otherwise.

Specified by:

dropRelation in class DbCore

Parameters:

tableName - the name of the table to be dropped

Returns:

TRUE iff the table had existed before it was removed, FALSE if nothing was done.

Throws:

M4Exception

getTestQuery

public java.lang.String getTestQuery()

Specified by:

getTestQuery in class DbCore

Returns:

a String that can be used as a query to test the DB connection.