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What else can I help you with?
Why do we need weak entity sets?
why do we need weak entity in database when we can make it strong entity?
Entity-relationship model additional features?
SpecializationThe process of designating sub groupings with in an entity set is called specialization.Weuse IS A relationship to represent specialization.ISA relationship may also be referred as super class-subclassrelationshipExample: Person IS A EmployeePerson IS A CustomerEmployee IS A ManagerGeneralizationHere the design process take place in bottom up manner.Multipleentity sets are synthesized into a higher level entity set on the basis of common features.Example: Employee and Customer entities can be synthesized into a higher level entity Person.Attribute inheritanceThe attributes of higher level entity set are inherited by lower level entity set.AggregationAggregation is an abstraction in which relationship sets are treated as higher level entity sets. Here a relationship set is embedded inside an entity set, and these entity sets can participate in relationships.
What is weak entity sets in dbms?
An entity set may not have sufficient attributes to form a primary key is called weak entity set. One with primary key is called strong entity set.
What is difference between generalization and specialization in DBMS?
DBMS: Data Base Management Systemgeneralization and specialization are important relationships that exist betweena higher level entity set and one or more lower level entity sets.1. generalization is the result of taking the union of two or more lower level entity sets to produce a higher level entity sets.specialization is the results of taking subsets of a higher level entity set to form a lower level entity sets.2. In generalization,each higher level entity must also be a lower level entity.In specialization,some higher level entities may not have lower-level entity sets at all.3. Specialization is a Top Down process where as Generalization is Bottom Up process.
What is the Distinction between condition defined and user defined constraints which of these constraints can system check?
In a generalization-specialization hierarchy, it must be possible to decide which entities are members of which lower level entity sets. In a conditiondefined design constraint, membership in the lower level entity-sets is evaluated on the basis of whether or not an entity satisfies an explicit condition or predicate.User-defined lower-level entity sets are not constrained by a membership condition; rather, entities are assigned to a given entity set by the database user. Condition-defined constraints alone can be automatically handled by the system. Whenever any tuple is inserted into the database, its membership in the various lower level entity-sets can be automatically decided by evaluating the respective membership predicates. Similarly when a tuple is updated, its membership in the various entity sets can be re-evaluated automatically
What comes in sets of 7?
Days of the week.
Er model.... Entity relationship diagram about how patient sets appointment to a doctor for check up....?
me2
What are finite sets?
They are sets with a finite number of elements. For example the days of the week, or the 12 months of the year. Modular arithmetic is based on finite sets.
What things come in sets of seven?
Days of the week underwear.
Who sets accounting standards for the government?
If the entity is a state or local governmental unit, it is subject to the reporting standards and requirements of the Government Accounting Standards Board.
Difference between disjoint and overlapping design constraints?
In a disjointness design constraint, an entity can belong to not more than one lower-level entity set. In overlapping generalizations, the same entity may belong to more than one lower-level entity sets. For example, in the employee-workteam example of the book, a manager may participate in more than one work-team.
What are the components of an entity relationship model?
Ok this is probably not what your after, but it may help, this information is a little old but should give you a bit of an answer if not ah welllll I tried :)http://tinyurl.com/zckcv
