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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.
Wiki User
∙ 9y ago
Wiki User
∙ 8y agoThe primary is the key that is used to identify a tuple uniquely . The primary key must always be unique . The primary key is also not null.
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How is the primary key used?
It is used as the unique identifier for each record and is used to sort the data
Candidate key and primary key differnece?
All Primary keys are definitely Candidate Keys. A Candidate key is one which can be used as a Primary key that is not null and unique. That is one of the candidate keys can be chosen as a primary key.A Candidate key is a Unique Key and it can be used to find out any particular Tuple (row) in a table. The following are the differences between A Candidate key and a Primary Key: 1) A Unique key can be null but not a Primary key 2) On a table we can have only 1 primary key but 'N' number of unique keys.
What is primary key constraint?
Primary Key is a Constraint Used to avoid Duplicate entries in database table and you define primary key the column doesn't allow NULL values.
How a primary key is fixed in a sql table?
A primary key field in a sql table is created using the PRIMARY KEY keyword. ex: CREATE TABLE tbl_employee ( emp_num VARCHAR(10), emp_name VARCHAR(100), PRIMARY KEY (emp_num)) The above script creates a table called tbl_employee and sets the emp_num field as the primary key
What does primary key mean in database form?
In a Database, more specifically a relational model, columns of one table that relate to columns of another table are called "key columns". There are two types of "key" columns. Foreign key and Primary Key. The Primary key of a table is usually a column within a table that contains unique data which cannot be duplicated. Think of it as a "unique identifier" column. You can actually create an array of key columns in a table to represent a unique series of values as well. (so PKey 1,2,3 are unique and no group of PKey's 1,2,3 will be the same, even though sometimes any one of those columns may contain a single value that has been duplicated, the consolidated value of all 3 will never be replicated). The Primary key of table A is linked to the Primary key of Table B for instance. Table B's Primary Key in this relationship is then called a "Foreign Key", meaning "The Primary Key of the OTHER table". That's a pretty basic understanding of how they work. There is a little bit more involved but this is the gist of it.
In a data base the primary key field is used to?
uniquely identify a record
Does a primary key maps an entire database?
yes a primary key can map the whole data base because if we take the example of any employee table in which ssn is the primary key with the help of this key we can determine that employee name and where he works on & which post ,his or her post,department no,location etc. so i think it can be true.
Does a primary key have to be an integer in an Access database?
No, it does not. A primary key can be different types of data, not just an integer.
What are the properties of primary key?
data cannot be repeated
How can a primary key be useful in controlling data redundancy?
controlling data redundancy
What is the primary key field of a database?
its a unique key use to identify data in database
How can you apply the primary key?
Primary key is the one which is uniquely defined in the attributes of a table. It can be used to pull any kind of data regarding a particular tuple in the table. PRIMARY IS ALSO A CANDIDATE KEY.
Does the data in a primary key field common to all records?
Yes
primary key?
attribute of an entity which uniquely identifies a specific instance of the data
What specifies the kind of data a field can contain and how the field is used?
primary key
What is a primary key what is its purpose and why do you use it?
A primary key is a unique identifier for each record in a database table. Its purpose is to ensure the uniqueness and integrity of the data within the table. It is used to uniquely identify each row, which allows for efficient data retrieval and modification, as well as establishing relationships between tables through foreign keys.
Which field MS Access will not allow you to delete?
A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.A primary key field.
