Relational Databases
Akopọ
Write a customer's address on every order they place and you have created a problem you will not notice for months. Then they move. Now some orders carry the old address and some carry the new one, both are in the same file, and nothing in the data says which is correct. The information has not been lost. It has been duplicated, and duplication is how data becomes untrustworthy.
This lesson explains what a database is, what makes one relational, and the five terms the specification examines: table, record, field, primary key and foreign key. Then it explains the reason the whole design exists. Splitting data across linked tables so that each fact is stored exactly once is what makes redundancy and inconsistency avoidable, and being able to say precisely how it does that is worth more marks than being able to name the parts.
Awọn Afojusun
- Explain the concept of a database. Explain the concept of a relational database. Understand the following important database concepts.
- table
- record
- field
- primary key
- foreign key.
- Understand that the use of a relational database facilitates the elimination of data inconsistency and data redundancy.
Àwòrán ọpọlọ
A ti ṣe àwòrán kókó yìí kí o lè rí bí àwọn èrò ṣe so pọ̀.
Ṣí àwòrán ọpọlọ nínú áàpù
Akọ̀wé Ẹ̀kọ́
Àkọsílẹ̀ Ẹ̀kọ́ Pípé wà lórí Ohun Èlò Green Bridge
Gba ohun èlò Green Bridge CBT sórí fóònù tàbí kọ̀mpútà rẹ fún gbogbo ilé ìkàwé IGCSE: ìwé ìdánwò àtijọ́, ìlànà ìdíwọ̀n, àwòrán èrò, káàdì ìkẹ́kọ̀ọ́ àti ẹ̀kọ́ ohùn.
Ìdánwò Ẹ̀kọ́
Oriire fun ipari ẹkọ lori Relational Databases. Ni bayi ti o ti ṣawari naa awọn imọran bọtini ati awọn imọran, o to akoko lati fi imọ rẹ si idanwo. Ẹka yii nfunni ni ọpọlọpọ awọn adaṣe awọn ibeere ti a ṣe lati fun oye rẹ lokun ati ṣe iranlọwọ fun ọ lati ṣe iwọn oye ohun elo naa.
Iwọ yoo pade adalu awọn iru ibeere, pẹlu awọn ibeere olumulo pupọ, awọn ibeere idahun kukuru, ati awọn ibeere iwe kikọ. Gbogbo ibeere kọọkan ni a ṣe pẹlu iṣaro lati ṣe ayẹwo awọn ẹya oriṣiriṣi ti imọ rẹ ati awọn ogbon ironu pataki.
Lo ise abala yii gege bi anfaani lati mu oye re lori koko-ọrọ naa lagbara ati lati ṣe idanimọ eyikeyi agbegbe ti o le nilo afikun ikẹkọ. Maṣe jẹ ki awọn italaya eyikeyi ti o ba pade da ọ lójú; dipo, wo wọn gẹgẹ bi awọn anfaani fun idagbasoke ati ilọsiwaju.
- What is a record in a relational database? A. One column of a table B. All the data about one individual item, held as one row C. The name of a table D. A link between two tables Answer: B
- What is a primary key? A. A field whose value uniquely identifies each record in a table B. The first field listed in a table C. A field that holds a value from another table D. The password used to open the database Answer: A
- A Booking table contains a field MemberID which holds values from the Member table's primary key. What is MemberID in the Booking table? A. A primary key B. A record C. A foreign key D. A table Answer: C
- What is data redundancy? A. Data that is no longer needed and can be deleted B. Storing the same piece of data more than once C. Data that has been encrypted D. A field with no value in it Answer: B
- Why can data inconsistency not occur if a fact is stored exactly once? A. Because a single copy cannot disagree with anything B. Because single copies are always encrypted C. Because a single copy takes up less space D. Because tables cannot be linked Answer: A
Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà
Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà
Awọn Iwe Itọsọna Ti a Gba Nimọran
Ṣe Adaṣe Awọn Ibeere Idanwo Adaṣe
Ṣe o fẹ ṣe adaṣe awọn ibeere idanwo adaṣe nipa Relational Databases? Ṣe igbasilẹ ohun elo Green Bridge CBT lati wọle si awọn ibeere idanwo adaṣe ati awọn ayẹwo adaṣe kikun fun koko-ọrọ yii.
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Gbogbo ohun ti o nilo lati ṣe dara julọ ninu JAMB, WAEC ati NECO.
