entity is a thing in the real world with an independent existance. and entity set is collection or set all entities of a particular entity type at any point of time.
take an example:
a company have many employees ,and these employees are defined as entities(e1,e2,E3....) and all these entities having same attributes are defined under ENTITY TYPE employee.and set{e1,e2,.....} is called entity set.
we can also understand this by an anology .
entity type is like fruit which is a class .we havn't seen any "fruit"yet though we have seen instance of fruit like "apple ,banana,mango etc.hence..
fruit=entity type=EMPLOYEE
apple=entity=e1 or e2 or e3
enity set= bucket of apple,banana ,mango etc={e1,e2......}
i am also having the same doubt please tell me the answers if u know
an entity type is a declaration that is used to represent fixed data.
A monolithic entity is a type of integrated circuit used in electrical engineering. It has both active and passive devices.
Are the closures and interiors of connected sets always connected, or the set of interior points? The Answer: No. There isn't always a connection inside connected sets.
We use the term net charge to define current due to unbalanced charges that flow.
a luminaire is defined as in bs7671
Staggering of brushes is nothing but displaying the positive brush sets in one direction and negative brush sets in the other direction. This ensures uniform wearing of commutator segments or surface (and avoids steps like between brush sets).
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.
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.
Supper Key- s a set of one or more attributes that taken collectively and allow us to identify entities with in entity set.
In DBMS a table contains one or more columns there columns are the attribute in DBMS FOR EXAMPLE---say you have a table named "employee information"which have the following columns ID,NAME,ADDRESS THEN id ,name address are the attributes of employee..................
the process of designating subgroupingswithin an entity set
relationship instance is an association of entity instances
the process of designating subgroupingswithin an entity set
d_id,d_name
converting er diagram to table in dbms?
why do we need weak entity in database when we can make it strong entity?
A weak entity set can always be make into strong entity set by adding to its attribute of its identifying entity set. For a weak entity set, we add columns to the table corresponding to the primary key of the strong entity set on which the weak set is dependent.
DBMS and RDBMS both are used for storing data. DBMS is the database management system that refers to the collection of interrelated data. RDBMS define relation between the tables in the database