4 A supermarket sells many products. Each product has a barcode. (a) Explain how the barcode is read at the supermarket checkout and how the price of the product is found. … … … … … … … … … … … … [6] (b) The supermarket stores data using a Solid State Drive (SSD). (i) Explain how an SSD stores data. … … … … … … [3] (ii) One advantage of an SSD rather than a Hard Disk Drive (HDD) is that it has no moving parts, so it is more durable. State one other advantage of the supermarket using SSD rather than HDD. … … [1]

4(a) Six from Max four from: − Scanned using a barcode reader − Shines (red) laser/light − Light is reflected back // white lines reflect light // black lines reflect less light − Sensors/photoelectric cells detect the light − Different reflections/bars give different binary/digital values // (pattern) converted to binary/digital values − Microprocessor interprets the data − Uses check digit error checking Max three from: − Database stores data/barcodes/products/prices − Barcode/value/key transmitted to database/system // Searches for barcode/value/key in the database/system… − … price is returned/found 6 4(b)(i) Max three from: − Flash storage − Uses transistors/controls gates/floating gates − Can be NAND/NOR technology // Can use flip-flops − Stores data by flashing it onto the chips/device − Controlling/using the flow of electrons through/using transistors/chips/gates − The electric current reaches the control gate and flows through to the floating gate to be stored − When data is stored the transistor is converted from 1 to 0 / 0 to 1 3 4(b)(ii) Max one from: − Faster read/write operation − Produces less heat // needs less cooling − Less susceptible to interference/magnets − Less power consumption 1 (a) To earn marks, you need to explain the process of barcode reading and price retrieval. This includes mentioning the use of a barcode reader, how light is reflected differently by black and white lines, how sensors detect this, and how the pattern is converted to digital values. For price retrieval, you must explain that the barcode value is transmitted to a database, which is then searched to return the product's price. (b)(i) You need to describe how flash storage works, mentioning the use of transistors/control gates/floating gates, NAND/NOR technology, and how data is stored by controlling the flow of electrons. (b)(ii) You must state one advantage of solid-state storage over hard disk drives, such as faster read/write operations, less heat production, or less susceptibility to interference.

5 A database table, CHOCBAR, is used to keep a record of chocolate bars sold. Chocolate bars are categorised by: • SIZE – small or large • FILLING – brief description, for example mint crunch • PRICE – price in Rupees, for example ₹2.50 • NUMBERSOLD – how many sold A database management system uses these data types: Text Number Currency Boolean (a) Select the most appropriate data type for these three fields from the four data types shown. Each data type must be different. State the reason why you chose the data type. SIZE data type … Reason … … PRICE data type … Reason … … NUMBERSOLD data type … Reason … … [3] (b) Complete the query-by-example grid below to display only the price, filling and number sold of small chocolate bars that have sold fewer than 10 bars. Field: Table: Sort: Show: Criteria: or: [3]

5(a) One mark for data type and reason SIZE text, expressed as a single word // Boolean, only two choices PRICE currency, needs to be expressed as Rupees/money NUMBERSOLD number, integer values/could be used in calculations 3 5(b) Field: SIZE FILLING PRICE NUMBERSOLD Table: CHOCBAR CHOCBAR CHOCBAR CHOCBAR Sort: Show:     Criteria: = "small" <10 or: One mark for correct rows Field, Table and Sort One mark for correct Show row One mark for correct Criteria row 3

5 A database table, APPLIANCE, is used to keep a record of kitchen appliances available for sale. The following data is stored for each appliance: • CATEGORY – washer, dishwasher, fridge or freezer • ECONOMYRATING – A, B, C or D • MANUFACTURER – Baku or ABC • PRICE – price in $ • CODE – a unique code allocated by the manufacturer e.g. B982 • STOCK – number in stock. The database management system uses these data types: Text Number Currency Boolean The ECONOMYRATING field and MANUFACTURER field have a data type of text. (a) Identify the most appropriate data type for each field from the four types shown. State the reason why you chose each data type. CATEGORY data type … Reason … … PRICE data type … Reason … … CODE data type … Reason … … STOCK data type … Reason … … [4] (b) Complete the query-by-example grid to display only the category, manufacturer and code of the appliances with an economy rating of A. Field: Table: Sort: Show: Criteria: or: [3]

5(a) CATEGORY – Text characters / words only used PRICE – Currency, the price is in dollars / money CODE – Text no calculations required, could be numbers or characters STOCK – Number, comparisons and calculations may be required 4 5(b) One mark for correct rows Field and Table One mark for correct Show row One mark for correct Criteria row Field: CATEGORY MANUFACTURER CODE ECONOMYRATING Table: APPLIANCE APPLIANCE APPLIANCE APPLIANCE Sort: Show:     Criteri a: ="A" or: 3

5 A database table, COMPUTER, is used to keep a record of computers available for sale. The following data is stored for each computer: • CATEGORY – desktop, laptop or tablet • WEIGHT – weight in kilograms • MANUFACTURER – ICN, Linoldo, Pear or JoeSing • PRICE – price in $ • CODE – a unique code allocated by the manufacturer, e.g. P771 • STOCK – quantity in stock. A database management system uses these data types: Text Number Currency Boolean The CATEGORY field and MANUFACTURER field have a data type of text. (a) Select the most appropriate data type for each field from the four types shown. State the reason why you chose the data type. WEIGHT data type … Reason … … PRICE data type … Reason … … CODE data type … Reason … … STOCK data type … Reason … … [4] (b) Complete the query-by-example grid to display only the category, manufacturer, price and code of the computers with weight of less than 2.5 kilograms. Field: Table: Sort: Show: Criteria: or: [3]

5(a) WEIGHT – Number, comparisons / calculations may be required PRICE – Currency, the price is in dollars / money CODE – Text, no calculations required, could be numbers or characters STOCK – Number, comparisons / calculations may be required 4 5(b) Field: CATEGORY MANUFACTURER PRICE CODE WEIGHT Table: COMPUTER COMPUTER COMPUTER COMPUTER COMPUTER Sort: Show:      Criteria: < 2.5 or: One mark for correct rows Field and Table One mark for correct Show row One mark for correct Criteria row 3

6 A database table, PLANT, is used to keep a record of plants sold by a nursery. The table has these fields: • NAME – name of plant • FLOWER – whether the plant flowers (True) or not (False) • POSITION – shade, partial shade or sun • SIZE – small, medium or large • PRICE – price in $ • NUMBERSOLD – how many sold A query-by-example grid has been completed to display only the price, name and number sold of small plants that do not flower. Field: NAME PRICE NUMBERSOLD SIZE FLOWER POSITION Table: PLANT Sort: Show: 3 3 3 riteria: = "shade" or: Identify the errors in the query-by-example grid. … … … … … … Rewrite the corrected query-by-example grid. Field: Table: Sort: Show: riteria: or: [5]

6 Any three from: • TABLE row not completed • POSITION column not required // POSITION criteria not required • No criteria set in the size column • No criteria set in the flower column Field: SIZE PRICE FLOWER NUMBERSOLD NAME Table: PLANT PLANT PLANT PLANT PLANT Sort: Show:      Criteria: ="small" False or: OR Field: SIZE PRICE FLOWER NUMBERSOLD NAME POSITION Table: PLANT PLANT PLANT PLANT PLANT PLANT Sort: Show:       Criteria: ="small" = False or: One mark for correct rows Field, Table and Show One mark for correct Criteria row 5

Cambridge IGCSE Computer Science · 0478

IGCSE Computer Science (0478) Databases past paper questions

Revise IGCSE Computer Science (0478) — Databases with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

31 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.