de.fuberlin.wiwiss.d2rq.dbschema

Class DatabaseSchemaInspector

java.lang.Object

de.fuberlin.wiwiss.d2rq.dbschema.DatabaseSchemaInspector

public class DatabaseSchemaInspector
extends Object

Inspects a database to retrieve schema information. TODO: All the dbType checks should be moved to the Vendor subclasses TODO: This usually shouldn't be used directly, but through the ConnectedDB. Except in the MappingGenerator. ConnectedDB is easier mockable for unit tests!

Author:

Richard Cyganiak (richard@cyganiak.de)

Field Summary

Fields

Modifier and Type	Field and Description
static int	KEYS_EXPORTED
static int	KEYS_IMPORTED

Constructor Summary

Constructors

Constructor and Description
DatabaseSchemaInspector(ConnectedDB db)

Method Summary

Methods

Modifier and Type	Method and Description
DataType	columnType(Attribute column)
List<Join>	foreignKeys(RelationName tableName, int direction) Returns a list of imported or exported (foreign) keys for a table.
RelationName	getCorrectCapitalization(RelationName relationName) Looks up a RelationName with the schema in order to retrieve the correct capitalization
boolean	isNullable(Attribute column)
boolean	isZerofillColumn(Attribute column)
List<Attribute>	listColumns(RelationName tableName)
List<RelationName>	listTableNames(String searchInSchema) Lists available table names
List<Attribute>	primaryKeyColumns(RelationName tableName)
Map<String,List<String>>	uniqueColumns(RelationName tableName) Returns unique indexes defined on the table.

Methods inherited from class java.lang.Object

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

Field Detail

KEYS_IMPORTED

public static final int KEYS_IMPORTED

See Also:

Constant Field Values

KEYS_EXPORTED

public static final int KEYS_EXPORTED

See Also:

Constant Field Values

Constructor Detail

DatabaseSchemaInspector

public DatabaseSchemaInspector(ConnectedDB db)

Method Detail

columnType

public DataType columnType(Attribute column)

Parameters:

column -

Returns:

The column's datatype, or null if unknown

isNullable

public boolean isNullable(Attribute column)

isZerofillColumn

public boolean isZerofillColumn(Attribute column)

listTableNames

public List<RelationName> listTableNames(String searchInSchema)

Lists available table names

Parameters:

searchInSchema - Schema to list tables from; null to list tables from all schemas

Returns:

A list of RelationNames

listColumns

public List<Attribute> listColumns(RelationName tableName)

primaryKeyColumns

public List<Attribute> primaryKeyColumns(RelationName tableName)

uniqueColumns

public Map<String,List<String>> uniqueColumns(RelationName tableName)

Returns unique indexes defined on the table.

Parameters:

tableName - Name of a table

Returns:

Map from index name to list of column names

foreignKeys

public List<Join> foreignKeys(RelationName tableName,
                     int direction)

Returns a list of imported or exported (foreign) keys for a table.

Parameters:

tableName - The table we are interested in

direction - If set to KEYS_IMPORTED, the table's foreign keys are returned. If set to KEYS_EXPORTED, the table's primary keys referenced from other tables are returned.

Returns:

A list of Joins; the local columns are in attributes1()

getCorrectCapitalization

public RelationName getCorrectCapitalization(RelationName relationName)

Looks up a RelationName with the schema in order to retrieve the correct capitalization

Parameters:

relationName -

Returns:

The correctly captialized RelationName