org.melati.poem.dbms
Class Postgresql

java.lang.Object
  org.melati.poem.dbms.AnsiStandard
      org.melati.poem.dbms.Postgresql

All Implemented Interfaces:

Dbms

public class Postgresql
extends AnsiStandard

A Driver for Postgresql. See http://www.postgresql.org/

Field Summary

Fields inherited from class org.melati.poem.dbms.AnsiStandard

schema

Constructor Summary

Postgresql()
Constructor.

Method Summary

boolean	canDropColumns(Connection con) Whether this DBMS can drop columns.
SQLPoemType	defaultPoemTypeOfColumnMetaData(ResultSet md) The simplest POEM type corresponding to a JDBC description from the database.
SQLPoemException	exceptionForUpdate(Table table, String sql, boolean insert, SQLException e) An exception appropriate for expressing what really went wrong during a write to the db.
String	getBinarySqlDefinition(int size) Accomodate different treatment of different sized binary data.
String	getStringSqlDefinition(int size) Accomodate String/Text distinction.
String	preparedStatementPlaceholder(PoemType type) Accomodate casting in placeholders.

Methods inherited from class org.melati.poem.dbms.AnsiStandard

alterColumnNotNullableSQL, booleanTrueExpression, canBeIndexed, canDropColumns, canRepresent, canStoreBlobs, caseInsensitiveRegExpSQL, createTableOptionsSql, createTableSql, createTableTypeQualifierSql, exceptionForUpdate, getConnection, getDriverClassName, getDriverLoaded, getFixedPtSqlDefinition, getForeignKeyDefinition, getIndexLength, getJdbcMetadataName, getLongSqlDefinition, getPrimaryKeyDefinition, getQuotedName, getQuotedValue, getSchema, getSqlDefaultValue, getSqlDefinition, givesCapabilitySQL, loadDriver, melatiName, selectLimit, setDriverClassName, setDriverLoaded, shutdown, sqlBooleanValueOfRaw, tableInitialisationSql, toString, unloadDriver, unreservedName

Methods inherited from class java.lang.Object

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

Constructor Detail

Postgresql

public Postgresql()

Constructor.

Method Detail

canDropColumns

public boolean canDropColumns(Connection con)
                       throws SQLException

Whether this DBMS can drop columns. Postgresql has been able to since 7.4

Parameters:

con - the current connection

Returns:

true if we can

Throws:

SQLException

See Also:

org.melati.poem.dbms.AnsiStandard#canDropColumns(java.sql.Connection)

preparedStatementPlaceholder

public String preparedStatementPlaceholder(PoemType type)

Accomodate casting in placeholders.

Specified by:

preparedStatementPlaceholder in interface Dbms

Overrides:

preparedStatementPlaceholder in class AnsiStandard

Parameters:

type - the type to cast

Returns:

the place holder string

See Also:

AnsiStandard.preparedStatementPlaceholder(org.melati.poem.PoemType)

getStringSqlDefinition

public String getStringSqlDefinition(int size)
                              throws SQLException

Accomodate String/Text distinction.

Specified by:

getStringSqlDefinition in interface Dbms

Overrides:

getStringSqlDefinition in class AnsiStandard

Parameters:

size - the string length (-1 means no limit)

Returns:

the SQL definition for a string of this size

Throws:

SQLException

See Also:

AnsiStandard.getStringSqlDefinition(int)

getBinarySqlDefinition

public String getBinarySqlDefinition(int size)
                              throws SQLException

Accomodate different treatment of different sized binary data.

Specified by:

getBinarySqlDefinition in interface Dbms

Overrides:

getBinarySqlDefinition in class AnsiStandard

Parameters:

size - how big the field is

Returns:

the keyword to use

Throws:

SQLException

See Also:

AnsiStandard.getBinarySqlDefinition(int)

defaultPoemTypeOfColumnMetaData

public SQLPoemType defaultPoemTypeOfColumnMetaData(ResultSet md)
                                            throws SQLException

The simplest POEM type corresponding to a JDBC description from the database.

Specified by:

defaultPoemTypeOfColumnMetaData in interface Dbms

Overrides:

defaultPoemTypeOfColumnMetaData in class AnsiStandard

Parameters:

md - the JDBC metadata

Returns:

the PoemType to use

Throws:

SQLException - potentially

See Also:

defaultPoemTypeOfColumnMetaData(java.sql.ResultSet)

exceptionForUpdate

public SQLPoemException exceptionForUpdate(Table table,
                                           String sql,
                                           boolean insert,
                                           SQLException e)

An exception appropriate for expressing what really went wrong during a write to the db. This gives the opportunity to try to interpret the getMessage text returned by the underlying driver, so that a more friendly error page can be put together for the user. Canonically, this is used to separate out "duplicate key" errors from more serious problems.

Specified by:

exceptionForUpdate in interface Dbms

Overrides:

exceptionForUpdate in class AnsiStandard

Parameters:

table - The table on which the update was affected

sql - The operation attempted, or possibly null

insert - Whether the operation was an INSERT as opposed to an UPDATE

e - The raw SQL exception: the routine is meant to try to interpret e.getMessage if it can

Returns:

an appropriate exception

See Also:

AnsiStandard.exceptionForUpdate(org.melati.poem.Table, java.lang.String, boolean, java.sql.SQLException)