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Also called a Key field.
We explicitly choose a primary key.A primary key should satisfy the following conditions: 1) it should not be null 2) it should be unique.
Yes. Primary key can be inserted to one field in the database. The field should be unique and not null.
A primary Key which uniquely identifies a row of table,primary key does not allow null values and also not allow duplicate values. Superkey is defined in the relational model of database organization as a set of attributes of a relation variable (relvar) for which it holds that in all relations assigned to that variable there are no two distinct tuples (rows) that have the same values for the attributes in this set. Equivalently a superkey can also be defined as a set of attributes of a relvar upon which all attributes of the relvar are functionally dependent. If you more information so you can visit this website:http://www.iyogibusiness.com
* Alternate key - An alternate key is any candidate key which is not selected to be the primary key * Candidate key - A candidate key is a field or combination of fields that can act as a primary key field for that table to uniquely identify each record in that table. * Compound key - compound key (also called a composite key or concatenated key) is a key that consists of 2 or more attributes. * Primary key - a primary key is a value that can be used to identify a unique row in a table. Attributes are associated with it. Examples of primary keys are Social Security numbers (associated to a specific person) or ISBNs (associated to a specific book). In the relational model of data, a primary key is a candidate key chosen as the main method of uniquely identifying a tuple in a relation. * Superkey - A superkey is defined in the relational model as a set of attributes of a relation variable (relvar) for which it holds that in all relations assigned to that variable there are no two distinct tuples (rows) that have the same values for the attributes in this set. Equivalently a superkey can also be defined as a set of attributes of a relvar upon which all attributes of the relvar are functionally dependent. * Foreign key - a foreign key (FK) is a field or group of fields in a database record that points to a key field or group of fields forming a key of another database record in some (usually different) table. Usually a foreign key in one table refers to the primary key (PK) of another table. This way references can be made to link information together and it is an essential part of database normalization
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yes
You should ask your teacher or just wait for the results.
I think super key is treated as the primary key because in a table their will be only one primary key.
Importance of primary key
We know that primary key is the one that is not null and is always unique. A primary key uniquely identifies a record in a table.
Primary key that is used to identify a record uniquely. Primary key is a key that always unique and not null. A system generated primary key is called surrogate key.Primary key is the one which is always unique and not null. Advantage of primary key that it helps in identifying a tuple uniquely.
Primary key is to set property ID as the primary key for the properties table.
A primary key is never null and is also unique . Example of primary key is create table emp (ecode integer NOT NULL PRIMARY KEY);
We designate one of the candidate key of a relation to be a primary key because that primary key is use for any foreign key references.