Section 6

Question 1

What are relational databases

Answer 1

allowing information to be accessed from various views through internal linking between entries.

Question 2

What are traditional flat file databases

Answer 2

present information from a single point of view and do not interact with other files.

Question 3

What is database reasearch

Answer 3

the act of analyzing and converting data into information that can be used in decision-making.

Question 4

What 2 layers make up a database typically

Answer 4

an application layer and a database management layer

Question 5

What does the application layer of a database do

Answer 5

communicates with the end user and does not directly manipulate the data. receives requests and uses the DBMS to obtain the results

Question 6

What does the management layer of a database do

Answer 6

returns the end user with results. Uses the application layer for requests and does the work. Add, delete, view data from the system.

Question 7

What is a database table composed of and what is it also known as

Answer 7

datasheet. composed of records and fields that hold data

Question 8

What does a “field” contain in a database

Answer 8

a single piece of data about the subject of a record

Question 9

What are 4 of the most common database models

Answer 9

flat-file, relational, hierarchical, and object-oriented

Question 10

What do flat-file databases consist of

Answer 10

stores data in a plain text file. each line of the text file holds one record. fields are separated by delimiters like spaces or commas. cannot contain multiple tables

Question 11

How are hierarchical databases structured

Answer 11

Data is organized in a tree structure, much like an organizational chart. There is one parent for each record, with optional nodes, forming sub-trees called segments. Access to the data is predictable and restricted to the paths in the trees.

Question 12

What do relational databases consist of

Answer 12

contain database tables that can be joined together in logical ways. each record has a unique identifier such as a product identification number or user name. the unique identifier is called a primary key. When the unique identifier is found on another table, it is called a foreign key.

Question 13

What are 3 factors to consider when choosing a database?

Answer 13

data retrieval speed, scalability, security

Question 14

What is a SELECT operation in SQL

Answer 14

takes rows from one table and creates a new table

SELECT PatientID, LastName FROM Patient

Question 15

SELECT - SQL

Answer 15

identifies records that are being requested

Question 16

‘*’ - SQL

Answer 16

everything from a table

Question 17

FROM - SQL

Answer 17

identifies table name

Question 18

WHERE - SQL

Answer 18

the condition the query is requesting

Question 19

What does the UNION operation do in SQL

Answer 19

combines distinct fields from multiple tables that have the same set of attributes and data types

SELECT PatientID, LastName FROM Patient
UNION
SELECT NurseID, LastName FROM Nurse;

Question 20

What is the product operation in SQL (CROSS JOIN)

Answer 20

creates a result table that includes all of the attributes from the two tables; each row of the second table is added to each row of the first table.

Question 21

How would you select a specific column from a table in SQL

Answer 21

tablename.columnname

Question 22

what is the difference between a product operation and union operation in SQL

Answer 22

the product operation (CROSS JOIN) combines every possible pair of rows from two tables to generate a new table, while the union operation (UNION) combines the rows from two tables into a single set, discarding duplicates.

Question 23

What is a join operation in SQL

Answer 23

combines two tables, but records are only appended when a matching criterion is met.

Question 24

What is the difference between an implicit join and explicit join in SQL

Answer 24

the syntax. in implicit join -

SELECT*
FROM Table1, Table2;

in explicit join-

SELECT*
FROM Table1 CROSS JOIN Table2;

Question 25

What are object-oriented (OO) databases

Answer 25

store complex data and relationships between data directly without using inter-table relations. An object database is a collection of objects, each with two components: data and instructions. for example, customer and orders are 2 fields. in the customer field, it would hold all of their info, and in the orders field, it would store their purchases and orders.

Question 26

What are NoSQL databases

Answer 26

an alternative to traditional relational databases in which data is placed in tables that are carefully designed before the database is built.

Question 27

What are document databases

Answer 27

store data elements in document-like structures that encode information in formats such as JSON

Question 28

What are graph databases

Answer 28

emphasize connections between data elements, storing related “nodes” in graphs to accelerate querying

Question 29

What are key-value stores

Answer 29

a NoSQL database that uses a simple data model that pairs a unique key like a username and its associated value in storing data elements (DOB, name, address, number, email address)

Question 30

What are wide-column stores

Answer 30

also called table-style databases, they store data across tables that can have very large numbers of columns

Question 31

What are cloud databases

Answer 31

optimized to work in a cloud environment.

Question 32

What is a data lake

Answer 32

a system of data stored in raw format. can include both structured data, such as tables, and unstructured data, such as audio and video recordings.

Question 33

What does a distributed database consist of

Answer 33

data residing on different machines. For instance, an international corporation might store and maintain local employer records at local sites, yet link those records via a network to create a single, distributed database.