A software system that facilitates the creation and maintenance and use of an electronic database
the number of tuple in a relation is called the cordinality of a relation?
difference between relation sehema and relation instance in dbms
Boyce -Codd normal form which is one of the forms of dbms noramlizations.normalization is converting the relations or tables in a standard form.bcnf is based on functional dependencies that take into account all candidate keys.a relation is in bcnf if every determinant has a candidate key..:)
d_id,d_name
Third normal form.
It is the DBMS that ensures the value of the foreign key matches another table's primary key when referential integrity constraints are enabled within the DBMS
more than one primary key to identify the record uniquely is called candidate key.
It is the number of attribute of its relation schema. Its is an association among two or more entities..
I am supposing that key means primary key.Superkey is any subset of attributes that uniquely identifies the tuples of a relation. This subset need not be minimal, that is, one can remove some attributes from it and it is still uniquely identifying. If all redundant attributes are removed you get a subset what is called primary key.
Relation: In Database a relation represents a table or an entity that contain diffrenet attributes.An Entity constructs a relation(table) in DBMS . Relationship: In Data base relationship is that how the two entities are connected to each other ,i.e what kind of relationship type they hold between them.Primary/Foreign key is used to specify or hold this relationship. By Tanzeel Ur Rahman Bhatti
In a Database Management System (DBMS), a relation is represented as a table consisting of rows and columns. Each row, or tuple, corresponds to a unique record, while each column, or attribute, represents a specific data field. Relations must adhere to the principles of atomicity, meaning each attribute should hold indivisible values, and they must maintain a unique identifier, usually a primary key, to distinguish each record. Additionally, all entries in a column should be of the same data type, ensuring consistency within the relation.
In DBMS, a relation instance refers to a particular set of data rows within a database table at a given point in time. It represents the actual values stored in the database for that specific table. Each row in a relation instance corresponds to a record or tuple within the table, containing values for each attribute.