Element Definitions:
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| eml-constraint |
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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 |
| ) |
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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.
Example:
Lineage:
New in EML 2.0
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| identifier |
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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 |
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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 |
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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 |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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Attributes:
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Required?:
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Default Value:
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Tooltip:
constraint name
Summary:
name of the field that this constraint is tied to
Description:
name of the field that this constraint is tied to. This
could also be the name of an independent constraint such
as a trigger or an autonumber generator.
Example:
LocationID, TABLE1_NUMBER_GEN1
Lineage:
New in EML 2.0
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| constraintDescription |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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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 |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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Attributes:
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Required?:
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Default Value:
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Tooltip:
table to which this constraint is tied
Summary:
table to which this constraint is tied
Description:
table to which this constraint is tied. In the instance
of a key, it is the name of the table in which it is
defined.
Example:
site_properties
Lineage:
New in EML 2.0
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| key |
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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 |
| ) |
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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 |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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Attributes:
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Required?:
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Default Value:
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| referencedEntityId |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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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.
Example:
site_properties
Lineage:
New in EML 2.0
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| referencedKey |
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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 |
| ) |
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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 |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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Attributes:
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Required?:
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Default Value:
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| cardinality |
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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:
Constrint 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 |
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Content of this field:
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Description of this field:
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| Type: xs:string |
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Attributes:
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Required?:
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Default Value:
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Tooltip:
Check Condition
Summary:
An SQL statement to be used as the condition for a check constraint.
Description:
A SQL statement to be used as 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 |
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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
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Derived from: xs:string
(by xs:restriction)
Allowed values:
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