Introduction

The Attributes Database allows applications to upload and retrieve custom data for NMPDR data objects. It uses the ERDB database system (which is also used by the SproutDatabase and the SaplingDatabase) to store the attributes. Attributes differ from conventional data in that they are unstructured: new attributes can be added without modifying the database design. A single attribute database services the entire NMPDR complex.

Attributes are organized by attribute key. Attribute values are assigned to objects. In the real world, objects have types and IDs; however, to the attribute database only the ID matters. In general, it is possible to determine the object type from the format of the ID, but it doesn't matter to the database.

The actual attribute values are stored as a relationship between the attribute keys and the objects. There can be multiple values for a single key/object pair.

Entities

AttributeGroup

A group is a named set of attribute keys. An attribute key can belong to many groups or none at all.

Groups provide a useful mechanism for classifying certain types of attribute keys. An attribute key's group membership is updated using a table of checkboxes in the attribute web interface. The interface also allows new groups to be created. There is a group for attributes that are only used for ProteinEncodingGroups? and another for attributes that require NMPDR support. Groups can also be used to specify attribute key white lists for individual applications.

• AttributeKey IsInGroup AttributeGroup (many-to-many)

AttributeGroup Table

Field	Type	Default	Description
id	name-string	n/a	Unique identifier for this AttributeGroup.

Index	Unique	Fields	Notes
idx0	yes	id	Primary index for AttributeGroup.

AttributeKey

An attribute key describes named values attached to a particular type of object. Each instance of this entity contains the attribute's description and its name. An attribute key name must consist of letters, numbers, periods, underscores, and/or hyphens.

• AttributeKey HasValueFor TargetObject (many-to-many)
• AttributeKey IsEvidencedBy TargetObject (many-to-many)
• AttributeKey IsInGroup AttributeGroup (many-to-many)

AttributeKey Table

Field	Type	Default	Description
id	name-string	n/a	Unique identifier for this AttributeKey.
relationship-name	name-string	n/a	Name of the relationship containing the attribute data. This relationship must look exactly like HasValueFor. The only difference is the table name.
description	text	n/a	Text describing the attribute. This should explain what the attribute means and what kinds of values are appropriate.

Index	Unique	Fields	Notes
idx0	yes	id	Primary index for AttributeKey.

TargetObject

An object represents a keyed thing to which an attribute can be assigned. In order to improve performance, this table has no data in it. It is simply required by the semantics of the database.

• AttributeKey HasValueFor TargetObject (many-to-many)
• AttributeKey IsEvidencedBy TargetObject (many-to-many)

TargetObject Table

Field	Type	Default	Description
id	string	n/a	Unique identifier for this TargetObject.

Index	Unique	Fields	Notes
idx0	yes	id	Primary index for TargetObject.

Relationships

HasValueFor

• Each AttributeKey relates to multiple TargetObjects.
• Each TargetObject relates to multiple AttributeKeys.

This relationship connects an attribute key to its objects. It contains the attribute values, and is therefore the primary data repository for the database.

HasValueFor Table

Field	Type	Default	Description
from-link	name-string	n/a	id of the source AttributeKey.
to-link	string	n/a	id of the target TargetObject.
subkey	string	n/a	Some attribute keys are split into two parts. The real key is controlled and must correspond to a key in the AttributeKey table. The second part of the key resides in this field. When the attribute value is presented to the user, the two parts of the key are joined together around the splitter value.
value	text	n/a	This is the actual attribute value. Note that a single key/object pair may in fact have many values, and therefore many entries in this table.

Index	Unique	Fields	Notes
idx0		value	This index allows searching for an attribute value by its prefix.
idx1		from-link, value	This index allows searching for values within keys.
idx2		from-link, to-link	This index sorts all the values for a single attribute key by the target object ID.
idxFrom		from-link, subkey	This index sorts all the values for a single attribute key by the subkey value.
idxTo		to-link, from-link, subkey	This index sorts all the values for an object by attribute key and the subkey.

IsEvidencedBy

• Each AttributeKey relates to multiple TargetObjects.
• Each TargetObject relates to multiple AttributeKeys.

This relationship connects a feature (target object) to its evidence attributes.

This table exists to separate evidence codes from other attributes for performance reasons. Evidence codes are built from scratch several times a week. Erasing an entire table is faster than erasing individual rows, so putting the evidence codes in their own private table provides significant benefits.

IsEvidencedBy Table

Field	Type	Default	Description
from-link	name-string	n/a	id of the source AttributeKey.
to-link	string	n/a	id of the target TargetObject.
subkey	string	n/a	Some attribute keys are split into two parts. The real key is controlled and must correspond to a key in the AttributeKey table. The second part of the key resides in this field. When the attribute value is presented to the user, the two parts of the key are joined together around the splitter value.
value	text	n/a	This is the actual attribute value. Note that a single key/object pair may in fact have many values, and therefore many entries in this table.

Index	Unique	Fields	Notes
idx0		value	This index allows searching for an attribute value by its prefix.
idx1		from-link, value	This index allows searching for values within keys.
idx2		from-link, to-link	This index sorts all the values for a single attribute key by the target object ID.
idxFrom		from-link, subkey	This index sorts all the values for a single attribute key by the subkey value.
idxTo		to-link, from-link, subkey	This index sorts all the values for an object by attribute key and the subkey.

IsInGroup

• Each AttributeKey relates to multiple AttributeGroups.
• Each AttributeGroup relates to multiple AttributeKeys.

This relationship connects an attribute key to the groups of which it is a member.

IsInGroup Table

Field	Type	Default	Description
from-link	name-string	n/a	id of the source AttributeKey.
to-link	name-string	n/a	id of the target AttributeGroup.

Index	Unique	Fields	Notes
idxFrom		from-link
idxTo		to-link