com.bigdata.relation

Class RelationSchema

java.lang.Object

com.bigdata.sparse.Schema

com.bigdata.relation.RelationSchema

All Implemented Interfaces:

Externalizable, Serializable

Direct Known Subclasses:

TripleStoreSchema

public class RelationSchema
extends Schema

A Schema for metadata about existing relations. Each relation corresponds more or less to a table in an RDBMS. A relation "exists" when there are indices for its data. An IRelation is a Class that allows you to read or write on the relation's data. Given the NAMESPACE of a relation, the RelationSchema specifies the CLASS that should be instantiated when an IRelation instance is created to operation on some relation's data. The schema is freely extensible and may be used to store additional properties that are made available to the IRelation when a new instance of that Class is instantiated. The relation namespace keys are Unicode.

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	CLASS The name of the property whose value is the name of the Class used to instantiate the ILocatableResource.
static String	COMMIT_TIME A dynamically injected property which can reveal the commit time from which a locatable resource was materialized.
static String	CONTAINER The name of the property whose value is namespace of the container (if any) for this the ILocatableResource resource having NAMESPACE as its resource identifier.
static RelationSchema	INSTANCE A shared instance.
static String	NAMESPACE The name of the property whose value is the namespace of the ILocatableResource (this is the primary key).

Constructor Summary

Constructors

Constructor and Description
RelationSchema() De-serialization ctor.

Method Summary

Methods inherited from class com.bigdata.sparse.Schema

appendPrimaryKey, fromKey, getKey, getName, getPrefix, getPrimaryKeyName, getPrimaryKeyType, getSchemaBytes, readExternal, toString, writeExternal

Methods inherited from class java.lang.Object

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

Field Detail

NAMESPACE

public static final String NAMESPACE

The name of the property whose value is the namespace of the ILocatableResource (this is the primary key).

CLASS

public static final String CLASS

The name of the property whose value is the name of the Class used to instantiate the ILocatableResource.

CONTAINER

public static final String CONTAINER

The name of the property whose value is namespace of the container (if any) for this the ILocatableResource resource having NAMESPACE as its resource identifier. When defined, this value MUST be a prefix of the value stored under the NAMESPACE property.

COMMIT_TIME

public static final String COMMIT_TIME

A dynamically injected property which can reveal the commit time from which a locatable resource was materialized.

See Also:

DefaultResourceLocator, AbstractResource, TODO This is a workaround for and should be removed when we replace the native long tx identifier with a thin interface.

INSTANCE

public static final transient RelationSchema INSTANCE

A shared instance.

Constructor Detail

RelationSchema

public RelationSchema()

De-serialization ctor.

See Also:

INSTANCE