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How to Insert Rows in Related Tables and Copy Data: SQL

Data pertaining to an entity can be stored in more than one table. Therefore, while adding information for a new entity, you need to insert new rows in all the related tables. In such a case, you need to first insert a row in the table that contains the primary key. Next, you can insert a row in the related table containing the foreign key.

For example, in the AdventureWorks database, the employee details are stored in the Person.Contact, HumanResources.Employee, HumanResources.EmployeeDepartmentHistory, and HumanResources.EmployeePayHistory tables.

To save the details for a new employee, you need to insert data in all these tables. The following statement insert data of a new employee into the database:

Inserting records in the Person.Contact table.

INSERT INTO Person.Contact VALUES (0, ‘Mr.’, ‘Steven’, NULL,’Fleming’,
NULL, ‘stevenfleming@adventure-works.com’, 1, ‘951-667-2401’,’B4802B37F8F077A6C1F2C3F50F6CD6C5379E9C79’, ‘3SA+edf=’, NULL, DEFAULT, DEFAULT)

INSERT INTO HumanResources.Employee VALUES (‘45879632’, 19978,’adventure-works/steven’, 185, ‘Tool Designer’, ‘ 1967-06-03 00:00:00.000’,
‘M’, ‘M’, ‘2006-08-01 00:00:00.000’, 1, 0, 0, 1, DEFAULT, DEFAULT)

INSERT INTO HumanResources.EmployeeDepartmentHistory VALUES (291, 2, 1, ‘2006-08-01 00:00:00.000’, NULL, DEFAULT)

INSERT INTO HumanResources.EmployeePayHistory VALUES (291,’2006-08-01 00:00:00.000’, 23.0769, 2, DEFAULT)

Copying Data from an Existing Table into a New Table

While inserting data in table, you might need to copy rows from an existing table to another table. You can do this by using the SELECT statement.

For example, in the AdventureWorks database, data for the employees with a remuneration rate of 35 or above is to be copied into a new table called Preferredemployee from the EmployeePayHistory table.
The following statements copy the values from the EmployeePayHistory table into the PreferredEmployee table:

SELECT * INTO PreferredEmployee
FROM HumanResources.EmployeePayHistory
WHERE Rate >= 35

The preceding statement will create a table named PreferredEmployee. The table will have the same structure as HumanResources.EmployeePayHistory.

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