Design And Implement Database Objects Flashcards Preview

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Flashcards in Design And Implement Database Objects Deck (13):
1

What is the mathematical definition of a relation?

Requires that you have no duplicated rows

TODO: Need better definition here

2

What are the criteria for first normal form?

1. All Columns must be atomic - that is, each column should represent one value

2. All rows of the table must contain the same number of values - no arrays

3

What is a surrogate key?

This is a artificial key that is normally used to provide performant uniqueness for a table row.

4

What is a natural key?

A unique values or unique combination of values that appear in row data that uniquely define the row.

5

What is Boyce-Codd Normal Form?

Every candidate key is identified, all attributes are fully dependent on a key, all columns must identify a fact about a key and nothing but a key.

6

What is second normal form

All attributes must be a fact about the entire primary key and not any non-primary key attributes.

7

What is third normal form?

All attributes must be a fact about the entire primary key and not any non-primary key attributes.

8

Would the following columns fit second normal form?

SKU (Key column 1)
Location (Key column 2)
ItemDisplayName
ItemPrice
PriceDate

No - this is because Item Display Name describes the SKU and is not specific to where the Item is sold.

No - because prices change over time. Either the PriceDate needs to be included in the Key or the price and price date need to be split out to another table.

9

TODO - Need a example question that differentiates between 2NF And 3NF

Need answer

10

What is a schema used for?

This is used to group together objects for security and logical ordering

11

What is Pascal-casing?

A naming convention what all the words are leading character capitalized and words are concatenated.

ItemPrice
PriceDate
CreateDateTime

12

What is camel casing?

A naming convention where the first word is all lower cases and subsequent word have the leading character uppercased. Also all words are concatenated.

itemPrice
priceDate
createDateTime

Note - this is for information purposes only. Probably won’t be on the exam.

13

What are the elements of a four part naming schema?

Server.Database.Schema.Object