1. Digital recordkeeping and preservation I
Databases : DML
ARK2100
Digital recordkeeping and preservation I
2017
Thomas Sødring
P48-R407

2. Data Manipulation Language (DML)
DML is a database language designed for manipulating data in relational databases
DML is used to insert, update or delete data in a table
INSERT
UPDATE
DELETE

3. DML INSERT Data is inserted into a relation one row at a time
The minimum you need is the primary key
Unless there are restrictions on other attributes e.g. NOT NULL
Even if you are inserting many rows (batch import), data is inserted one tuple at a time
Data that is across two rows in different tables can be inserted together
There is no requirement for transaction
Remember referential integrity

4. INSERT INTO TABLE (attributtelist) VALUES (valuelist);

5. INSERT INTO TABLE VALUES ();

6. INSERT Car # Example 1 INSERT INTO Car
(registrationNr, chassisNr, colour, manufacturer, model)
VALUES
("ZQ10000", " ", "black", "Audi", "A3");
# Example 2
INSERT INTO Car VALUES

7. INSERT Car

8. INSERT Car ??

9. INSERT Car

10. After INSERT Car

11. INSERT Car (multiple rows)
INSERT INTO Car
(registrationNr, chassisNr, colour, manufacturer, model)
VALUES
("ZQ10001", " ", "red", "Audi", "A5"),
("ZQ10002", " ", "blue", "VW", "Golf");

12. INSERT Car (multiple rows)

13. After INSERT Car (multiple rows)

14. Take a look at Car

15. SQL UPDATE A tuple can be updated/changed with the UPDATE command
You can change the values of fields
Many tuples can be updated simultaneously with one command
Updated one at a time
Remember, there is usually no [CTRL] + [Z] (undo) button
You can do a lot of harm to a database if you are not careful

16. UPDATE
SET
WHERE;

17. UPDATE TABLE SET Attribute='value' WHERE;

18. UPDATE Car SET registrationNr = "ZQ10099" WHERE

19. UPDATE Car

20. After UPDATE Car

21. UPDATE Car SET colour = "pink" WHERE registrationNr = "ZQ10099" ;

22. UPDATE Bil

23. After UPDATE Car

24. Take a look at Car

25. UPDATE Car
UPDATE Car SET
colour = "red";
What will happen here?

26. Update Car

27. Take a look at Car

28. DELETE
FROM
WHERE;

29. DELETE FROM TABLE WHERE;

30. DELETE Car
DELETE FROM Car
WHERE
registrationNr = "ZQ10099" ;

31. DELETE Car

32. After DELETE Car

33. Take a look at Car

34. DELETE Car
DELETE FROM Car;
What will happen here?

35. Fill up the Car relation
The following link will allow you to insert a lot of data into the Car relation
The username is your studentId
Use the password you created for mysql/phpmyadmin
The database must exist and contain a table called Car

36. Car with many records

37. TRUNCATE Car; Truncate
We can easily empty the table using the truncate command
You need to run the script again to fill up the table
TRUNCATE Car;

38. Summary Manipulation of data is done using insert, update or delete
It's very easy to create problems with your data
Always use the WHERE clause when you create an UPDATE or DELETE command
Care must be taken especially with these as there is usually no undo button
The application on top of the database might break if you aren't careful