Since relation is a set, and tuples are element of a set, according to set theory, the elements of a set are not ordered.
rows are called tuples
DBMS stands for database management system. DBMS reduce data redundancy as it checks if the data is duplicate and if duplicate then store it as a single record.
There are many reasons why SQL allows duplicate tuples (rows):To store non-unique values.To simply remove primary keys, unique indexes, and unique constraints.It allows this if there is no unique constraint.
ExtensionThe extension of a given relation is the set of tuples appearing in that relation at any given instance. The extension thus varies with time. It changes as tuples are created, destroyed, and updated.
extension in a relation is set of tuples appearing in relation at any given instance . it varies with time .it changes tuple are created ,destroyed and update
What are the features of a dbms
In a relation we have number of tuple R ={t1,t2,t3.....tn}, nd they follow integrity constraints nd each tuple has a primary key pk.if any of the d two tuple have same attribute. for instance t1=t2 then its pk wud be same too.. but this violates the key constraint.. hence duplicacy not allowed in tuple... enjoy Rijo Rajan
The entity integrity constraint states that no primary key value can be null. This is because the primary key value is used to identify individual tuples in a relation. Having null value for the primary key implies that we cannot identify some tuples. This also specifies that there may not be any duplicate entries in primary key column key row.
No Duplicate Tuples - A relation cannot contain two or more tuples which have the same values for all the attributes. i.e., In any relation, every row is unique. • Tuples are unordered - The order of rows in a relation is immaterial. • Attributes are unordered - The order of columns in a relation is immaterial. • Attribute Values are Atomic - Each tuple contains exactly one value for each attribute. It may be noted that many of the properties of relations follow the fact that the body of a relation is a mathematical set.
NA_ what are highlights of advanced DBMS what are highlights of advanced DBMS what are highlights of advanced DBMS
no, Java is not dbms.. Java is a programming language Dbms is database
dbms