In files, there is a key associated with each record which is used to differentiate among different records. For every file there is at least one set of keys that is unique. Such a key is called ?
In files, there is a key associated with each record which is used to differentiate among different records. For every file there is at least one set of keys that is unique. Such a key is called ?
The correct option is B Primary key
In files, there is a key associated with each record
which is used to differentiate among different records. For every file there is
at least one set of keys that is unique. Such a key is called primary key.
A primary key 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. A relational database must always have
one and only one primary key.
A primary key's main
features are: It must contain a unique value for each row of data. It cannot
contain null values.
In files, there is a key associated with each record which is used to differentiate among different records. For every file there is at least one set of keys that is unique. Such a key is called primary key.
A primary key 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. A relational database must always have one and only one primary key.
A primary key's main features are: It must contain a unique value for each row of data. It cannot contain null values.
