Computer Science (9-1) - 0984 CIE

Databases

Gbogbo ọrọ náà

Almost every organisation stores data: a shop's stock, a school's students, a library's books. A database is how that data is kept in a structured way so it can be searched, sorted and totalled in an instant. This topic shows you how a single-table database is built and how to pull exactly the data you want out of it using SQL.

You will learn how to define a single-table database from a set of requirements, choose suitable data types for each field, understand and pick a primary key, and read, complete and write SQL queries using SELECT, FROM, WHERE, ORDER BY, SUM and COUNT. By the end you should be able to design a table and query it confidently, just as the exam expects.

Ebumnobi

1 Define a single-table database from given data storage requirements
2 Suggest suitable basic data types
3 Understand the purpose of a primary key and identify a suitable primary key for a given database table
4 Read, understand and complete structured query language (SQL) scripts to query data stored in a single database table

Akọmọ Ojú-ẹkọ

Databases sit behind nearly every website, app and business system, and SQL is a near-universal language for querying them, the same SQL works across almost any database software. The exam asks you to design a single-table database and to read and complete SQL scripts, so these are directly examined, practical skills.

Ọ dị na ngwa Green Bridge

Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.

Akwụkwọ ndụmọdụ zuru oke nwere eserese

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Mụọ n'ụzọ na-enweghị ịntaneti, oge ọbụla, ebe ọbụla

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Ọ dị na Android, Windows, macOS, na Linux

Ayẹwo Ẹkọ

Ekele diri gi maka imecha ihe karịrị na Databases. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

In a database, a single row containing all the fields about one object is called a: A. field B. record C. table D. query Answer: B
Which data type is most suitable for a price such as 3.99? A. integer B. Boolean C. real D. character Answer: C
What is the main purpose of a primary key? A. to sort the records B. to uniquely identify each record C. to count the records D. to encrypt the data Answer: B
Which SQL clause is used to return only records that meet a condition? A. ORDER BY B. SELECT C. WHERE D. COUNT Answer: C
Which SQL function counts how many records meet a condition? A. SUM B. COUNT C. ORDER BY D. TOTAL Answer: B