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What else can I help you with?
foreign key?
when a primary key from one table is stored as an attribute of another table
What is the primary key for the properties table?
Primary key is to set property ID as the primary key for the properties table.
Can a primary key refer to a whole table?
No, a primary key do not refers to the whole table .A primary key refers to a field in the table that is not null and unique.
Why must the primary key of a parent table be determined before the foreign key in the child table?
Because the foreign key is copied from the primary key of the parent table
Is it necessarily that a foreign key is primary key in other table?
It is not mandatory that is must be a primary key but it must be a unique key in the other table.
What does the term foreign key mean in databases?
The foreign key is used as a reference in a table to the primary key of another table. For example: consider a table employee with id(primary key), name, address,department_id(foreign key) as its fields.Another table department with fields department_id(primary key) and dept_name. So, department_id is primary key in department table and foreign key in employee table.
Can a primary key be a foreign key?
Yes, a primary key can also be a foreign key. This is known as a composite key, where one or more columns in a table are both primary keys for that table and also act as foreign keys linking to another table.
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
Can super key be as primary key?
I think super key is treated as the primary key because in a table their will be only one primary key.
What is primery key?
primary key is a column or set of columns (called composite primary key ) that identify the table & make every table unique .value of a primary key can not duplicated & can not be NULL .
How do you create a primay key in Oracle?
You can create a primary key column in an oracle table using the PRIMARY KEY keyword. Assuming you have an employee table that has employee information and has a column called emp_num. you can create a primary key in the table using the below command. ALTER TABLE tbl_employee_info add CONSTRAINT emp_pk PRIMARY KEY (emp_num) If you execute the above command in your database, emp_num will become the primary key of the table tbl_employee_info.
What is a primary key what is its purpose and why do you use it?
What is a Primary Key?The PRIMARY KEY constraint uniquely identifies each record in a database table.Primary keys must contain unique values.A primary key column cannot contain NULL values.Each table should have a primary key, and each table can have only ONE primary key.The primary key is defined by using the PRIMARY KEY constraint when either creating a table or altering a table.*Example of primary key :- customer Nowhat is its purpose and why do you use it?In relational database design, a unique key or primary key is a candidate key to uniquely identify each row in a table.
