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Domain Model
A domain model helps you to define the restriction and extraction models and makes the HTML data model render more compact and concise. A domain model doesn’t influence the export behaviour and is not needed to do data exports.
A domain model is a partitioning of the entire data model into
smaller
sets of functionally related tables.
Definition
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Domain a set of functionally related tables.
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Domain Model set of domains D with a partial order part-of ⊆ D²
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Top-level domain domain which is not part-of another domain.
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Subdomain domain which is not a Top-level domain.
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Extension E(d) of a domain is the set of all tables of d and d‘s subdomains. E(d)=d∪{t|∃d’:d’ part-of d ∧ t∈d’}
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two different domains are disjoint.
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the union of all domains is the set of all tables.
Example
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Tables
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ADDRESS
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DEPARTMENT
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EMPLOYEE
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Associations
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DEPARTMENT → ADDRESS
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EMPLOYEE → ADDRESS
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EMPLOYEE → DEPARTMENT
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Domains
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DEPARTMENTS={DEPARTMENT}
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EMPLOYEES={EMPLOYEE}
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ADDRESSES={ADDRESS}
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ADDRESSES part-of DEPARTMENTS
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ADDRESSES part-of EMPLOYEES
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DEPARTMENTS part-of EMPLOYEES
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Extensions
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E(ADDRESSES)={ADDRESS}
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E(DEPARTMENTS)={DEPARTMENT, ADDRESS}
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E(EMPLOYEES)={EMPLOYEE, DEPARTMENT, ADDRESS}
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Composites
A composite is a group of tables to be treated in the same way as a single table. A composite consists of a main table representing the entire composition and several component tables. The name of a composite is the name of the main table. Components are not mentioned in the domain model but are implicitly part of the main table’s domain.
Generating domain specific restriction models
It is possible to automatically generate a restriction model for each domain restricting the entry into the domain. A restriction model for a domain contains restrictions for each association from a table outside of d to a table in d. Note that dependencies are unrestrictable.
Example
| NO-ADDRESSES.csv | ||
|---|---|---|
| DEPARTMENT | ADDRESS | ignore |
| EMPLOYEE | ADDRESS | ignore |
| NO-DEPARTMENTS.csv | ||
|---|---|---|
| EMPLOYEE | DEPARTMENT | ignore |
| NO-EMPLOYEES.csv |
|---|
Generating domain
specific extraction models
It is also possible to automatically generate an extraction model (without subject-definition of course) for each domain including all restriction models of other domains except sub-domains.
Example
| ADDRESSES | ||||
|---|---|---|---|---|
| <subject> | <condition> | <limit> | NO-EMPLOYEES.csv;NO-DEPARTMENTS.csv | |
| DEPARTMENTS | ||||
|---|---|---|---|---|
| <subject> | <condition> | <limit> | NO-EMPLOYEES.csv | |
| EMPLOYEES |
|---|