com.googlecode.jdbw.metadata
Class Table

java.lang.Object
  com.googlecode.jdbw.metadata.Table

All Implemented Interfaces:

Comparable<Table>

public class Table
extends Object
implements Comparable<Table>

Table is the primary object you deal with in a database server, they contain at least one column (often more) making the definition of the table and 0 or more rows, which each row has a value for each column.

A table normally has a primary key, a kind of unique index where each row has a value that is unique for within this table. This primary key consists of at least (and normally) one column but could be a combination of several. If you look for a particular row in the table and you know the value of the primary key column(s), this row can be fetched very quickly.

Other than a primary key, a table may also have one or more indexes. An index will make certain lookups much more efficient, you can find more information about how this works in the description of the Index class.

Author:

Martin Berglund

See Also:

Schema, Column, Index

Constructor Summary

Table(MetaDataResolver metaDataResolver, Schema schema, String tableName)

Method Summary

int	compareTo(Table o)
List<Index>	getAllIndexes()
Catalog	getCatalog()
Column	getColumn(int columnIndex) Retrieves a column by index the database
Column	getColumn(String columnName) Looks up one column
Map<String,Column>	getColumnMap()
List<Column>	getColumns()
Map<String,Index>	getIndexMap()
String	getName()
int	getNrOfColumns()
Index	getPrimaryKey()
Schema	getSchema()
Index	getUniqueKey() This method will return you the primary key if there is one, otherwise scan through the list of indexes and return the first available unique index.
void	invalidateCache() This table class will cache the columns and indexes after reading them from the database server once, this method will clear the cache, forcing them to be re-read.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Table

public Table(MetaDataResolver metaDataResolver,
             Schema schema,
             String tableName)

Method Detail

getCatalog

public Catalog getCatalog()

Returns:

The catalog which this table sorts under, i.e. the owner of this table's schema

getName

public String getName()

Returns:

Name of the table

getSchema

public Schema getSchema()

Returns:

The schema which owns the table

getUniqueKey

public Index getUniqueKey()
                   throws SQLException

This method will return you the primary key if there is one, otherwise scan through the list of indexes and return the first available unique index. If none is found, it returns null.

Returns:

First available unique index or null

Throws:

SQLException - In an error occurred while reading information from the database

getPrimaryKey

public Index getPrimaryKey()
                    throws SQLException

Returns:

The primary key of this table, represented as an Index or null if there is no primary key

Throws:

SQLException - In an error occurred while reading information from the database

invalidateCache

public void invalidateCache()

This table class will cache the columns and indexes after reading them from the database server once, this method will clear the cache, forcing them to be re-read.

getColumns

public List<Column> getColumns()
                        throws SQLException

Returns:

List of columns in the table, expected to be in order

Throws:

SQLException - In an error occurred while reading information from the database

getAllIndexes

public List<Index> getAllIndexes()
                          throws SQLException

Returns:

All indexes, including the primary key, on this table

Throws:

SQLException - In an error occurred while reading information from the database

getColumn

public Column getColumn(String columnName)
                 throws SQLException

Looks up one column

Parameters:

columnName - Name of the column to retrieve

Returns:

Column representing the column or null if there was no column by this name in the table

Throws:

SQLException - In an error occurred while reading information from the database

getColumn

public Column getColumn(int columnIndex)
                 throws SQLException

Retrieves a column by index the database

Parameters:

columnIndex - Index of the column (starting from 0)

Returns:

Column representing the column at this index in the table

Throws:

SQLException - In an error occurred while reading information from the database

getNrOfColumns

public int getNrOfColumns()
                   throws SQLException

Returns:

Number of columns this table has

Throws:

SQLException - In an error occurred while reading information from the database

compareTo

public int compareTo(Table o)

Specified by:

compareTo in interface Comparable<Table>

getColumnMap

public Map<String,Column> getColumnMap()
                                throws SQLException

Returns:

Map (column name to Column object) of all columns in this table

Throws:

SQLException - In an error occurred while reading information from the database

getIndexMap

public Map<String,Index> getIndexMap()
                              throws SQLException

Returns:

Map (index name to Index object) of all indexes in this table, including the primary key

Throws:

SQLException - In an error occurred while reading information from the database

toString

public String toString()

Overrides:

toString in class Object