Element Definitions:
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eml-constraint |
Content of this field:
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Description of this field:
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Elements:
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Required?:
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How many:
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A sequence of ( |
identifier | Optional | Multiple Times |
constraint | Optional | Multiple Times |
) |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Relational integrity constraint descriptors
Summary:
Describes the relational integrity constraints of a relational
database.
Description:
Describes the relational integrity constraints of a relational
database. This includes primary keys, foreign keys, unique keys, etc.
When an eml-constraint module is created, it should be linked into
a dataset using the "triple" element, and all of the entities that
are referenced in the constraints should be accessible within that
same package.
Example:
Lineage:
New in EML 2.0
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identifier |
Content of this field:
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Description of this field:
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Elements:
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Required?:
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How many:
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Attributes:
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Required?:
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Default Value:
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Tooltip:
Unique identifier
Summary:
The unique identifier of this metadata file or object.
Description:
The identifier field provides a unique identifier for this
metadata documentation. It will most likely be part of a
sequence of numbers or letters that are meaningful in a
larger context, such as a metadata catalog. That larger
system can be identified in the "system" attribute. Multiple
identifiers can be listed corresponding to different catalog
systems.
Example:
<identifier system="metacat">nceas.3.2</identifier>
Lineage:
The 'identifier' field is derived from the eml-dataset
meta_file_id filed in EML 1.4.
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constraint |
Content of this field:
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Description of this field:
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Tooltip:
Integrity constraint
Summary:
Information about the integrity constraint being defined.
Description:
Complete information needed to reconstruct this integrity
constraint for enforcement in a system such as a relational
database management system.
Example:
Lineage:
New in EML 2.0
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constraintType |
Content of this field:
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Description of this field:
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Elements:
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Required?:
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How many:
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Attributes:
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Required?:
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Default Value:
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Tooltip:
type of constraint
Summary:
the type of constraint being defined
Description:
the type of constraint being defined. This is
what kind of constraint this is.
Example:
PrimaryKey, ForeignKey, UniqueKey
Lineage:
New in EML 2.0
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constraintName |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
constraint name
Summary:
Name of the constraint
Description:
Name of the constraint. This is typically an informative
name that can be used to refer to the constraint itself.
Example:
party_name_fk_1
Lineage:
New in EML 2.0
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constraintDescription |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
constraint description
Summary:
description of the constraint
Description:
description of the constraint. Any additional
information that may be needed to fully understand
the constraint.
Example:
Lineage:
New in EML 2.0
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entityId |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Constrained Entity
Summary:
Entity to which this constraint applies
Description:
Entity to which this constraint applies. This should be
an identifer that matches one of the "identifier"
elements for an entity that is linked into the package
with a triple. The constraint document itself should be
linked into the package as a member.
Example:
knb.78.3
Lineage:
New in EML 2.0.0
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key |
Content of this field:
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Description of this field:
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Elements:
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Required?:
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How many:
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A sequence of ( |
attributeName | Optional | Multiple Times |
) |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Key
Summary:
The set of attributes to which this constraint applies.
Description:
The set of attributes to which this constraint applies.
For a primary key or a unique key, the set of attributes must be
identifying. For a foreign key, the set of attributes must match
an identifying key in the referenced entity. For a not null
constraint, the key indicates the attribute which should not
be null.
Example:
Lineage:
New in EML 2.0
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attributeName |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Attribute Name
Summary:
Name of an attribute found in the identified entity
Description:
Name of an attribute that can be found in the identified
entity. This name will be unique within an entity and
specifies that the attribute participates in the key that
is being defined.
Example:
Lineage:
New in EML 2.0
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referencedEntityId |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Referenced Entity ID
Summary:
The id of the parent-entity in a foreign key constraint.
Description:
This field contains the id of the entity to which a foreign key
refers, otherwise known as the parent-entity or parent-table.
This should be an identifer that matches one of the "identifier"
elements for an entity that is linked into the package
with a triple. The constraint document itself should be
linked into the package as a member.
Example:
knb.79.4
Lineage:
New in EML 2.0
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referencedKey |
Content of this field:
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Description of this field:
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Elements:
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Required?:
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How many:
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A sequence of ( |
attributeName | Optional | Multiple Times |
) |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Key
Summary:
The set of attributes to which a foreign key constraint refers.
Description:
The set of attributes to which a foreign key constraint refers.
If the key refers to the primary key in the referenced entity,
then the "referencedKey" is optional. For a foreign key, the
set of attributes must match an identifying key in the
referenced entity.
Example:
Lineage:
New in EML 2.0
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attributeName |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Attribute Name
Summary:
Name of an attribute found in the identified entity
Description:
Name of an attribute that can be found in the identified
entity. This name will be unique within an entity and
specifies that the attribute participates in the key that
is being defined.
Example:
Lineage:
New in EML 2.0
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cardinality |
Content of this field:
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Description of this field:
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Elements:
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Required?:
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How many:
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Attributes:
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Required?:
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Default Value:
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Tooltip:
Constraint Cardinality
Summary:
The cardinality of a foreign key constraint.
Description:
Indicates the cardinality (zero, one, many) of a foreign key constraint.
Example:
Lineage:
New in EML 2.0
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checkCondition |
Content of this field:
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Description of this field:
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Type: xs:string |
Attributes:
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Required?:
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Default Value:
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Tooltip:
Check Condition
Summary:
An SQL statement or other language implementation of
the condition for a check constraint.
Description:
A SQL statement or other language implementation of
the condition for a check constraint.
Generally this provides a means for constraining the
values within and among entities.
Example:
(year > 1900 and year < 1990)
Lineage:
New in EML 2.0
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Attribute Definitions:
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system |
Type: xs:string
Use: optional
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Tooltip:
Catalog system
Summary:
The catalog system in which this identifier is used.
Description:
This element gives the name of the catalog system in which
this identifier is used. It is useful to determine the
scope of the identifier, and to determine the semantics
of the various subparts of the identifier. Unresolved issue:
can or should this be a URI/URL pointing to the catalog
system, or just the name?
Example:
<identifier system="metacat">nceas.3.2</identifier>
Lineage:
New to EML 2.0.
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Complex Type Definitions:
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Simple Type Definitions:
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Derived from: xs:string
(by xs:restriction)
Allowed values:
- UniqueKey
- PrimaryKey
- ForeignKey
- NotNull
- Check
- OtherConstraint
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Derived from: xs:string
(by xs:restriction)
Allowed values:
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