What is primary key 11th class?

Question

Primary Key: A candidate key that is primarily chosen for unique identification of tuples in a Relation. Any subset of Primary key should not be Primary key. Alternate Key: Candidate keys that not chosen as primary key are the alternate keys. Example: In a LIBRARY Table. 17 мар. 2018 г.

What is the primary key answer?

A primary key, also called a primary keyword, is a key in a relational database that is unique for each record. It is a unique identifier, such as a driver license number, telephone number (including area code), or vehicle identification number (VIN). A relational database must always have one and only one primary key.

What is primary key class?

A primary key class must meet these requirements: The access control modifier of the class must be public. The properties of the primary key class must be public or protected if property-based access is used. The class must have a public default constructor.

What is primary key and example?

A primary key is a column -- or a group of columns -- in a table that uniquely identifies the rows in that table. For example, in the table below, CustomerNo, which displays the ID number assigned to different customers, is the primary key. CUSTOMERS. CustomerNo.

What is primary key and secondary?

A primary key is the field in a database that is the primary key used to uniquely identify a record in a database. A secondary key is an additional key, or alternate key, which can be use in addition to the primary key to locate specific data.

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