0
What else can I help you with?
How functional dependency is related to database table design?
The functional dependency is related to the database table design through the foreign and primary keys. The foreign and primary keys are functionally dependent on each other.
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
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.
Could a table only have one primary key and only one foreign key?
Yes it could. It would have a primary key for its own use and it could then have a foreign linking it to another table. If it is only linked to one other table, then it would only need one foreign key. It is also possible to have the same foreign key linking to more than one 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.
The foreign key uniquely identifies a record in a table T or F?
False. A foreign key is a primary of one table that is in another table. A foreign key can be repeated, so it does not uniquely identify records in the table where it is a foreign key.
How do you identify the primary key and the foreign keys?
The primary key is identified as a unique identifier for a table, ensuring that no two records have the same value in that column or set of columns. It is typically defined during the table design phase and can be a single column or a combination of columns. Foreign keys, on the other hand, are fields in a table that create a link between that table and another table; they reference the primary key of another table to establish a relationship. To identify foreign keys, look for columns that are intended to reference the primary key of another table, often indicated by naming conventions or constraints defined in the database schema.
foreign key?
when a primary key from one table is stored as an attribute of another table
What is Relationship between a primary and a foreign key?
A primary key is one or more colums in a table whose values would uniquely identify a row in that table. A foreign key is a one or more columns in one table that are used to reference rows in another table. In a properly designed 3NF schema, the foreign key columns should correspond to the primary key columns of the table being referenced.
Is a foreign key field always on the one side of a one-to-many relationship between two tables?
No. The foreign key is always on the many side. A foreign key is a field that is a primary key in another table, not in the table it is in. It can therefore be repeated in the table it is, so it can act as the many side. In its own table, it is the primary key, and only appears once.
Can a table have two foreign keys?
Yes, a table can have multiple foreign keys. Each foreign key can reference a primary key in a different table, establishing relationships between the tables. This allows for complex data structures and relationships in a relational database. For example, a "Orders" table could have foreign keys referencing both a "Customers" table and a "Products" table.
What is the difference between a primary key and a foreign key?
A primary key uniquely identifies each record in a table and ensures data integrity. A foreign key establishes a relationship between two tables, referencing the primary key of another table to enforce referential integrity.
