javatools.database

Class PostgresDatabase

java.lang.Object

javatools.database.Database

javatools.database.PostgresDatabase

public class PostgresDatabase
extends Database

This class is part of the Java Tools (see http://mpii.de/yago-naga/javatools). It is licensed under the Creative Commons Attribution License (see http://creativecommons.org/licenses/by/3.0) by the YAGO-NAGA team (see http://mpii.de/yago-naga). The class PostgresDatabase implements the Database-interface for a PostgreSQL data base. Make sure that the file "postgresql-version.jdbc3.jar" of the Postgres distribution is in the classpath. When using Eclipse, add the file via Project ->Properties ->JavaBuildPath ->Libraries ->ExternalJARFile.
Example:

     Database d=new PostgresDatabase("user","password");     
     d.queryColumn("SELECT foodname FROM food WHERE origin=\"Italy\"")
     -> [ "Pizza Romana", "Spaghetti alla Bolognese", "Saltimbocca"]
     Database.describe(d.query("SELECT * FROM food WHERE origin=\"Italy\"")
     -> foodname |origin  |calories |
        ------------------------------
        Pizza Rom|Italy   |10000    |
        Spaghetti|Italy   |8000     |
        Saltimboc|Italy   |8000     |        

This class also provides SQL datatypes (extensions of SQLType.java) that behave according to the conventions of Postgres. For example, VARCHAR string literals print inner quotes as doublequotes.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PostgresDatabase.Postgretext
static class	PostgresDatabase.PostgreVarchar

Nested classes/interfaces inherited from class javatools.database.Database

Database.CommitTransactionSQLException, Database.ConnectionBrokenSQLException, Database.InitTransactionSQLException, Database.Inserter, Database.RollbackTransactionSQLException, Database.StartAutoCommitSQLException, Database.TransactionSQLException

Field Summary

Fields

Modifier and Type	Field and Description
static PostgresDatabase.Postgretext	postgretext
static PostgresDatabase.PostgreVarchar	postgrevarchar
protected java.lang.String	schema Holds the default schema

Fields inherited from class javatools.database.Database

connection, description, driver, fetchsize, inserters, java2SQL, MINCOLUMNWIDTH, resultSetConcurrency, resultSetType, SCREENWIDTH, type2SQL

Constructor Summary

Constructors

Constructor and Description
PostgresDatabase() Constructs a non-functional PostgresDatabase for use of getSQLType
PostgresDatabase(java.lang.String user, java.lang.String password, java.lang.String database, java.lang.String host, java.lang.String port)
PostgresDatabase(java.lang.String user, java.lang.String password, java.lang.String database, java.lang.String host, java.lang.String port, boolean useSSL) Constructs a new Database from a user, a password and a host
PostgresDatabase(java.lang.String user, java.lang.String password, java.lang.String database, java.lang.String host, java.lang.String port, java.lang.String schema) Constructs a new Database from a user, a password and a host, setting also the (preferred) schema (public stays fallback schema)
PostgresDatabase(java.lang.String user, java.lang.String password, java.lang.String database, java.lang.String host, java.lang.String port, java.lang.String schema, boolean useSSL) Constructs a new Database from a user, a password and a host, setting also the (preferred) schema (public stays fallback schema)

Method Summary

Modifier and Type	Method and Description
java.lang.String	autoincrementColumn() Produces an SQL fragment representing column properties for an autoincrementing integer column s.t.
java.lang.String	cast(java.lang.String value, java.lang.String type) Produces an SQL fragment casting the given value to the given type *
protected void	commitTransaction() commits the transaction aggregated so far if the commit fails the transaction is rolled back!
void	connect() connects to the database specified
void	createTable(java.lang.String name, java.lang.Object... attributes) Creates or rewrites an SQL table.
java.lang.String	getSQLStmntIFNULL(java.lang.String a, java.lang.String b) returns the database system specific expression for ifnull functionality i.e.
boolean	jarAvailable() TRUE if the required JAR is there
void	lockTableReadAccess(java.util.Map<java.lang.String,java.lang.String> tablesAndAliases) Locks a table in read mode, i.e.
void	lockTableWriteAccess(java.util.Map<java.lang.String,java.lang.String> tablesAndAliases) Locks a table in write mode, i.e.
static void	main(java.lang.String[] args)
void	releaseLocksAndEndTransaction() releases all locks the connection holds, commits the current transaction and ends it
void	setExclusiveSchema(java.lang.String s) Sets the default schema
void	setSchema(java.lang.String s) Sets the default schema
void	startTransaction() Initiates a transaction by disabling autocommit and enabling transaction mod Note: In Postgres transactions have a name e

Methods inherited from class javatools.database.Database

appendFixedLen, attemptReconnect, close, close, close, close, connected, createIndex, createIndexCommand, createIndices, createPrimaryKey, createView, describe, describe, dumpCSV, dumpQueryAsCSV, endTransaction, endTransaction, executeQuery, executeUpdate, executeUpdateQuery, exists, existsTable, finalize, flush, format, formatNullToNull, getConnection, getFetchsize, getResultSetConcurrency, getResultSetType, getSQLType, getSQLType, getSQLType, getValidityCheckTimeout, indexName, isAutoReconnectingOnSelect, isAutoReconnectingOnUpdate, limit, loadCSV, makeCSV, makeCSVForQuery, newInserter, newInserter, newInserter, offset, prepareQuery, query, query, query, query, queryValue, reconnect, resetTransaction, runInterface, setAutoReconnectOnSelect, setAutoReconnectOnUpdate, setFetchsize, setResultSetConcurrency, setResultSetType, setValidityCheckTimeout, toString

Methods inherited from class java.lang.Object

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

Field Detail

schema

protected java.lang.String schema

Holds the default schema

postgrevarchar

public static PostgresDatabase.PostgreVarchar postgrevarchar

postgretext

public static PostgresDatabase.Postgretext postgretext

Constructor Detail

PostgresDatabase

public PostgresDatabase()

Constructs a non-functional PostgresDatabase for use of getSQLType

PostgresDatabase

public PostgresDatabase(java.lang.String user,
                        java.lang.String password,
                        java.lang.String database,
                        java.lang.String host,
                        java.lang.String port,
                        boolean useSSL)
                 throws java.lang.InstantiationException,
                        java.lang.IllegalAccessException,
                        java.lang.ClassNotFoundException,
                        java.sql.SQLException

Constructs a new Database from a user, a password and a host

Throws:

java.lang.ClassNotFoundException

java.lang.IllegalAccessException

java.lang.InstantiationException

java.sql.SQLException

PostgresDatabase

public PostgresDatabase(java.lang.String user,
                        java.lang.String password,
                        java.lang.String database,
                        java.lang.String host,
                        java.lang.String port)
                 throws java.lang.InstantiationException,
                        java.lang.IllegalAccessException,
                        java.lang.ClassNotFoundException,
                        java.sql.SQLException

Throws:

java.lang.InstantiationException

java.lang.IllegalAccessException

java.lang.ClassNotFoundException

java.sql.SQLException

PostgresDatabase

public PostgresDatabase(java.lang.String user,
                        java.lang.String password,
                        java.lang.String database,
                        java.lang.String host,
                        java.lang.String port,
                        java.lang.String schema,
                        boolean useSSL)
                 throws java.lang.InstantiationException,
                        java.lang.IllegalAccessException,
                        java.lang.ClassNotFoundException,
                        java.sql.SQLException

Constructs a new Database from a user, a password and a host, setting also the (preferred) schema (public stays fallback schema)

Throws:

java.lang.InstantiationException

java.lang.IllegalAccessException

java.lang.ClassNotFoundException

java.sql.SQLException

PostgresDatabase

public PostgresDatabase(java.lang.String user,
                        java.lang.String password,
                        java.lang.String database,
                        java.lang.String host,
                        java.lang.String port,
                        java.lang.String schema)
                 throws java.lang.InstantiationException,
                        java.lang.IllegalAccessException,
                        java.lang.ClassNotFoundException,
                        java.sql.SQLException

Constructs a new Database from a user, a password and a host, setting also the (preferred) schema (public stays fallback schema)

Throws:

java.lang.InstantiationException

java.lang.IllegalAccessException

java.lang.ClassNotFoundException

java.sql.SQLException

Method Detail

connect

public void connect()
             throws java.sql.SQLException

connects to the database specified

Specified by:

connect in class Database

Throws:

java.sql.SQLException

setSchema

public void setSchema(java.lang.String s)
               throws java.sql.SQLException

Sets the default schema

Throws:

java.sql.SQLException

setExclusiveSchema

public void setExclusiveSchema(java.lang.String s)
                        throws java.sql.SQLException

Sets the default schema

Throws:

java.sql.SQLException

createTable

public void createTable(java.lang.String name,
                        java.lang.Object... attributes)
                 throws java.sql.SQLException

Creates or rewrites an SQL table. Attributes is an alternating sequence of a name (String) and a type (from java.sql.Type).

Overrides:

createTable in class Database

Throws:

java.sql.SQLException

jarAvailable

public boolean jarAvailable()

Description copied from class: Database

TRUE if the required JAR is there

Overrides:

jarAvailable in class Database

cast

public java.lang.String cast(java.lang.String value,
                             java.lang.String type)

Produces an SQL fragment casting the given value to the given type *

Overrides:

cast in class Database

getSQLStmntIFNULL

public java.lang.String getSQLStmntIFNULL(java.lang.String a,
                                          java.lang.String b)

returns the database system specific expression for ifnull functionality i.e. ifnull(a,b) returns b if a is null and a otherwise

Overrides:

getSQLStmntIFNULL in class Database

autoincrementColumn

public java.lang.String autoincrementColumn()

Produces an SQL fragment representing column properties for an autoincrementing integer column s.t. if used during table creation a column can declared to get by default an integer value assigned according to an internal self-incrementing sequence counter Example: createTable("tableWithSingleAutoIncrementingIDColumn", "ID", autoincrementColumn())

Overrides:

autoincrementColumn in class Database

startTransaction

public void startTransaction()
                      throws Database.InitTransactionSQLException

Initiates a transaction by disabling autocommit and enabling transaction mod Note: In Postgres transactions have a name e

Overrides:

startTransaction in class Database

Throws:

Database.InitTransactionSQLException

commitTransaction

protected void commitTransaction()
                          throws Database.TransactionSQLException

commits the transaction aggregated so far if the commit fails the transaction is rolled back!

Overrides:

commitTransaction in class Database

Throws:

Database.TransactionSQLException

lockTableWriteAccess

public void lockTableWriteAccess(java.util.Map<java.lang.String,java.lang.String> tablesAndAliases)
                          throws java.sql.SQLException

Locks a table in write mode, i.e. other db connections can only read the table, but not write to it

Overrides:

lockTableWriteAccess in class Database

Throws:

java.sql.SQLException

lockTableReadAccess

public void lockTableReadAccess(java.util.Map<java.lang.String,java.lang.String> tablesAndAliases)
                         throws java.sql.SQLException

Locks a table in read mode, i.e. only this connection can read or write the table

Overrides:

lockTableReadAccess in class Database

Throws:

java.sql.SQLException

releaseLocksAndEndTransaction

public void releaseLocksAndEndTransaction()
                                   throws java.sql.SQLException

releases all locks the connection holds, commits the current transaction and ends it

Overrides:

releaseLocksAndEndTransaction in class Database

Throws:

java.sql.SQLException

main

public static void main(java.lang.String[] args)