relationship type,degree, cardinality, optionality terms confusion
database, database-design
Solution
Ok here is the explanation
1.Degree. This is the number of entities involved in the relationship and it is usually 2 (binary relationship) however Unary and higher degree relationships can be exists.
2.Cardinality. This specifies the number of each entity that is involved in the relationship there are 3 types of cardinality for binary relationships
- one to one (1:1)
- one to many (1:n)
- many to many (n:m)
hope this will clear your mind. Please communicate for more information
Problem
I currently studying database i've seen degree and cardinality uses as same term, or in some other degree is defined as no. of entities involved in a relationship and further catogories as unary, binary and trenary. Some placed degree is defined as The degree of a relationship type concerns the number of entities within each entity type that can be linked by a given relationship type. Cardinality is minimum and maximun number of entity occurrence associated with one occurrence of the related entity cardinality types as `1 to 1` , `1 to many` , `many to many`. or min and max cardinality. Min degree is optionality and maximum degree is cardinalty. what is the difference between degree and cardinaltiy ? In another context cardinality is a number of rows in table and degree is a number of columns. So what i'm i suppose to write if question is asked "Define cardinality ?". Can somebody explain ?