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What is a non key attribute in normalization?
An attribute is another name for a field in a table. Some attributes are used as keys to help specifically identify individual records,like a code number or reference number for example. Most attributes are not used as keys. Any of those are non-key attributes.
Discuss the difference between a composite key and a composite attribute.How would each be indicated in an ERD?
Attribute is the property of entity.The composite attribute is like address(where street no,house no,town name all include).Composite key is also an attribute,but only which attribute are work as a unique identifier. Example:> In an ERD if vendor placed with orders then order(order day, order number) vendor(vendor code,vendor address) Here, order and vendor both are entity and order number, vendor code both are Composite key(because those are unique)but vendor address is a Composite attribute and order day(may be not unique)is an attribute only. So, we can conclude that all attribute not Composite key.
What is data dependency in DBMS?
Data dependency in DBMS refers to the relationship between different data elements within a database. There are three main types: functional dependency (one attribute determines another), partial dependency (part of a composite key determines other attributes), and transitive dependency (dependency between non-key attributes). Understanding data dependencies is crucial for database normalization and maintaining data integrity.
What is second normal form in DBMS?
Second normal form is valid in a table which have composite primary key which is made with the combination of two columns.So if we have A,B,C,D,E attributes in our table and C,D are fully functional dependent on A,B.But E is partially functional dependent on A,B,Mean if we use Only B to define E coloumn then that will be suffecent.so then we use 2nd normal form & we create two tables with coloumns attributes A,B,C,D and the other table with coloumns attribute B,E.That will be called second normal form.
Which is an attribute?
An attribute is a characteristic or feature of an object or entity. It helps to describe or define the object by providing specific information about it. Examples of attributes include color, size, shape, and weight.
What is a non key attribute in normalization?
An attribute is another name for a field in a table. Some attributes are used as keys to help specifically identify individual records,like a code number or reference number for example. Most attributes are not used as keys. Any of those are non-key attributes.
What are key attribute and non key attribute?
Attributes can be classified as identifiers or descriptors. Identifiers, more commonly called keys or key attributes uniquely identify an instance of an entity. If such an attribute doesn't exist naturally, a new attribute is defined for that purpose, for example an ID number or code. A descriptor describes a non-unique characteristic of an entity instance. An entity usually has an attribute whose values are distinct for each individual entity. This attribute uniquely identifies the individual entity. Such an attribute is called a key attribute. For example, in the Employee entity type, EmpNo is the key attribute since no two employees can have same employee number. Similarly, for Product entity type, ProdId is the key attribute. There may be a case when one single attribute is not sufficient to identify entities. Then a combination of attributes can solve this purpose. We can form a group of more than one attribute and use this combination as a key attribute. That is known as a composite key attribute. When identifying attributes of entities, identifying key attribute is very important.
What are the requirements for a relation to be in Second Normal Form?
A relation is in second normal form (2NF) if any of the following conditions apply: The primary key consists of only one attribute No non-primary key attribute exists in the relation Every non-primary key attribute is functionally dependent on the full set of primary key attributes
Non-prime attribute in DBMS?
Prime attribute are part of any candidate key. Non-prime attribute are not part of any candidate key.
Is foreign key a non key attribute?
a key to a different table
What conditions are required for 3NF violation to occur?
A relation violates third normal form (3NF) if it has a transitive dependency where a non-prime attribute depends on another non-prime attribute (which itself is not a candidate key). This means that a non-prime attribute is functionally dependent on another non-prime attribute rather than on a candidate key.
What is key attribute and entity in database?
The attribute (or combination of attributes) that is unique for every entity instance e.g.: the account number of an account, the employee id of an employee etc.
Explain different types of attributes with example in DBMS.?
Different types of attributes in DBMS are:Key or non key attributesRequired or optional AttributesSimple or composite AttributesSingle-valued and multi-valued AttributesStored, Coded or derived Attributes
What is the prime attribute in DBMS?
prime attributes are the attributes of a candidate key which will give uniqueness. a candidate key is (the subset of superkey) which gives uniqueness. Super key is the maximum set of attributes that can provide uniqueness example ABCDE is a super key AB CD DE are the candidate keys s.t. AB is the primary key. CD and DE are the secondary/alternate keys.
Can you sort a table without a primary key?
Yes. You can sort on any attribute or combination of attributes in a table (in SQL using the "order by" clause). Of course the sort is only as good as the "uniqueness" of the attribute you sort on, hence a combination of attributes may be helpful. A primary key is, by definition, unique across all rows in the table.
What part of speech is attributes?
Attributes is a noun (plural form of attribute) and a verb (third person singular conjugation of attribute).
What does best non-physical attribute of a person mean?
The best non-physical attribute of a person refers to qualities or characteristics that are not related to physical appearance, such as kindness, intelligence, empathy, or sense of humor. These attributes reflect a person's character, values, and personality.
