Logical Data Modeling - Constraint

Data System Architecture


A constraint is a metadata rule that expresses a condition or restriction in natural language text or in a machine readable language for the purpose of declaring some data or process semantics.


  • Structure: All rows must have the same number of columns
  • Data domain: All value in a column must have the same type
  • Relationship: A child cannot have three parents
  • Business rule: A product cannot be send to a client that was not verified.

Documentation / Reference

Discover More
Card Puncher Data Processing
Business - Rule

A business rule is a rule that constrains some aspect of the business process. According to the white paper by the Business Rules Group, a business...
Data System Architecture
Data Property - ACID (atomicity, consistency, isolation, durability)

In computer science, ACID (atomicity, consistency, isolation, durability) is a set of properties that guarantee transactions are processed reliably. They defines a concurrency model. Traditional database...
Data System Architecture
Logical Data Modeling - Data Integrity

Data/Database integrity ensures that data entered into the database is: accurate, correct (valid), and consistent. Three basic types of integrity are: Entity integrity, allowing no two rows...
Without Data Model
Logical Data Modeling - Data Model

A data model is an (abstract) model that describes how data are represented and accessed. Data models formally define entity and relationships among entities for a domain of interest. schema A data...
Data System Architecture
Logical Data Modeling - Multiplicity

Multiplicity constrain the number of values that may be contained by a container (ie entity set) The multiplicity specifies valid cardinalities of the collection it represents. (It denotes the possible...
Data System Architecture
Logical Data Modeling - Rule

A rule is a statement that defines or constrains: data or procedure Ogilvy on Advertising A rule is the first block of a language (declarative and procedural)
Data System Architecture
Logical Data Modeling - Value (Operand)

A value may be obtained by: observation or measurement Values may represents the structural characteristic of: an entity (case) or a relationship A value is stored in a field (cell). ...
Data System Architecture
Relational Data Modeling - (Integrity) (Constraints|action assertions)

Constraints are a set of rule inside a relational database that declare consistency rules in order to: enforce data integrity and give information on the data (used by the query optimizer) Every...

Share this page:
Follow us:
Task Runner