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Define a relation ?
Relation - A relations is a named two-dimensional table of data. Mathematically, a relation can be described as a subset of the cartesian product of a list of domains. Each relation consists of a set of named columns and an arbitrary number of rows. The columns correspond to the areas describing each tuple within the table or relation. The rows correspond to each instance of the entity elaborates through the table or relation.
I need to Map an E-R diagram to a relational schema
Discuss the problem of Spurious tuples and how we may prevent it. Ans: A spurious tuple is, mainly, a record in a database that gets created while two tables are joined bad
Durability : This property necessitates that once a transaction has committed, the changes made by it be never lost because of subsequent failure. Thus, a transaction is also a bas
If R1 and R2 are two union compatible relations or functions, then the result of R3 = R1 ∩R2 is the relation that contains all tuples that are in both the relations In other words,
Update or Modify operation alters the existing values. If these operations alter the value that is the foreign key also, the only check need is the similar as that of the Insert op
Define garbage collection. Garbage may be formed also as a side effect of crashes. Periodically, it is essential to find all the garbage pages and to add them to the list of fr
Define multivalued dependency and 4NF. Ans: Multivalued Dependency - Assume R be a relation schema and let α ⊆ R and β ⊆ R. The multivalued dependency α →→β holds o
discuss the purpose of the concurrency control?
Explain heap file with advantages? Heap File is an unordered set or a group of records, stored on a set of pages. This class gives basic support for inserting, updating, select
Define the terms entity, attribute, role and relationship between the entities, giving examples for each of them. Ans: Entity: An entity is a "thing" or "object" in th
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