joi, 24 decembrie 2009
Uneori nu facem decat sa ne irosim timpul...
vineri, 18 decembrie 2009
sâmbătă, 12 decembrie 2009
Ce ati vrea sa va aduca mosul?
joi, 10 decembrie 2009
Silent night
We wish you a merry christmas
O! ce veste minunata
Astazi s-a nascut hristos
Astazi s-a nascut hristos
Mesia chip luminos
Laudati si cantati
Si va bucurati!!!!!!
Mititel infasatel
In scutec de bumbacel
Laudati si cantati
Si va bucurati
Neaua ninge
Nu-l atinge
Vantul bate
Nu-l razbate
Laudati si cantati
Si va bucurati!!!!!!!
Si de acum
Pana-n vecie
Mila domnului sa fie
Laudati si cantati
Si va bucuratï!!!!!!
Jingle Bells - Versuri
Dashing through the snow
In a one horse open sleigh
O'er the fields we go
Laughing all the way
Bells on bob tails ring
Making spirits bright
What fun it is to laugh and sing
A sleighing song tonight
Oh, jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a one horse open sleigh
Jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a one horse open sleigh
A day or two ago
I thought I'd take a ride
And soon Miss Fanny Bright
Was seated by my side
The horse was lean and lank
Misfortune seemed his lot
We got into a drifted bank
And then we got upsot
Oh, jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a one horse open sleigh
Jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a one horse open sleigh yeah
Jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a one horse open sleigh
Jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a one horse open sleigh
duminică, 6 decembrie 2009
Andra ft. Adi Cristescu – Colt de suflet
Numai sa te uit
Azi nici piesa noastra
Nu o mai ascult.
Cafeneaua-n care ne-ntalneam
Acum o ocolesc
Mi-aminteste de intaiul "Te iubesc!"...
Am sters si pozele cu noi
Nu vreau sa dau timpu`napoi
Am renuntat la tot ce aveam
Si-mi amintea de tine
Am sters si pozele cu noi
Nu vreau sa dau timpu`napoi
Am renuntat la tot ce-mi amintea de tine...
Insa ce nu pot uita
Este amintirea ta
O pastreza inima
Intr`un colt de suflet
Si oricat as incerca
Nu te voi putea uita
Te pastreaza inima
intr`un colt de suflet
Si ar mai fi ceva..
Ce nu voi putea uita
Sufletul nu ma lasa
Azi e ziua noastra...(BIS)
Am facut tot ce-am stiut sa fac
Numai sa te uit
Dar nu stiam ca`mi va fi dor
Atat de mult
Spun mereu k nu mai simt nimic
Cand ma-ntreaba cineva
Dar daca nu mai simt nimic
De ce imi mai sta gandul la ea?
Am sters si pozele cu noi
Nu vreau sa dau timpu`napoi
Am renuntat la tot ce`mi amintea de tine...
Insa ce nu pot uita
Este amintirea ta
O pastreza inima
Intr`un colt de suflet
Si oricat as incerca
Nu te voi putea uita
Te pastreaza inima
Intr`un colt de suflet...
cand e liniste
Aud vocea ta
Cand sunt singura
Simt atingerea ta
Cand inchid ochii mei
Vad ochii tai
Nu mai pot rezista...
Insa ce nu pot uita
Este amintirea ta
O pastreza inima
Intr`un colt de suflet
Si oricat as incerca
Nu te voi putea uita
Te pastreaza inima
Intr`un colt de suflet...
(BIS)
Si ar mai fi ceva..
Ce nu voi putea uita
Sufletul nu ma lasa
Azi e zïua noastra...(BIS)
Cadouri...
PS! INTERZIS COPIILOR CU VARSTA INTRE 1 SI 13 ANI!
marți, 24 noiembrie 2009
Quiz: Introduction to Functions
1. The following statement represents a multi-row function. True or False?
SELECT MAX(salary)
FROM employees
True (*)
False
2. The conversion function TO_CHAR is a single row function. True or False?
True (*)
False
3. Will the following statement return one row?
SELECT MAX(salary), MIN(Salary), AVG(SALARY)
FROM employees;
No, it is illegal. You cannot use more than one multi-row function in a SELECT statement
Yes, it will return the highest salary, the lowest salary and the average salary from all employees (*)
Yes, it will return the highest salary from each employee
Yes, it will return the average salary from the employees table.
4. The following statement represents a multi-row function. True or False?
SELECT UPPER(last_name)
FROM employees;
True
False (*)
5. The function COUNT is a single row function. True or False?
True
False (*)
Quiz: Comparison Operators
1. Which of the following are examples of comparison operators used in the WHERE clause?
=, >, <, <=, >=, <>
between ___ and ___
in (..,..,.. )
like
is null
All of the above (*)
2. When using the “LIKE” operator, the % and _ symbols can be used to do a pattern-matching, wild card search. True or False?
True (*)
False
3. Which of the following WHERE clauses would not select the number 10?
WHERE hours BETWEEN 10 AND 20
WHERE hours <= 10
WHERE hours <>10 (*)
WHERE hours IN (8,9,10)
4. Which statement would select salaries that are greater than or equal to 2500 and less than or equal to 3500? Choose two correct answers.
WHERE salary >= 2500 AND salary <= 3500 (*)
WHERE salary <=2500 AND salary >= 3500
WHERE salary BETWEEN 2500 AND 3500 (*)
WHERE salary BETWEEN 3500 AND 2500
Quiz: Logical Comparisons and Precedence Rules
1. Which of the following are examples of logical operators that might be used in a WHERE clause. (Choose Two)
AND, OR (*)
> <, =, <=, >=, <>
NOT IN (*)
LIKES
None of the above
2. What will be the results of the following selection?
SELECT *
FROM employees
WHERE last_name NOT LIKE ‘A%’ AND last_name NOT LIKE ‘B%’
All last names that begin with A or B
All last names that do not begin with A or B (*)
No rows will be returned. There is a syntax error
All rows will be returned
3. Which of the following would be returned by this SQL statement:
SELECT First_name, last_name, department_id
FROM employees
WHERE department_id IN(50,80)
AND first_name LIKE ‘C%’
OR last_name LIKE ‘%s%’
FIRST_NAME LAST_NAME DEPARTMENT_ID
Shelly Higgins 110
FIRST_NAME LAST_NAME DEPARTMENT_ID
Curtis Davies 50
FIRST_NAME LAST_NAME DEPARTMENT_ID
Randall Matos 50
FIRST_NAME LAST_NAME DEPARTMENT_ID
Michael Hartstein 20
All of the above (*)
4. Which of the following is earliest in the rules of precedence?
Concatenation operator
Logical condition
Comparison condition
Arithmetic operator (*)
5. Find the clause that will give the same results as:
SELECT *
FROM d_cds
WHERE cd_number NOT IN(90, 91, 92);
WHERE cd_id <=90 and cd_id >=92;
WHERE cd_id NOT LIKE (90, 91, 92);
WHERE cd_id != 90 and cd_id != 91 and cd_id != 92; (*)
WHERE cd_id != 90 or cd_id != 91 or cd_id!= 92;
6. Which logical operators in the WHERE clause means “Not Equal To”? (Choose Two)
NOT IN (…) (*)
=+
<> (*)
><
7. Which of the following statements best describes the rules of precedence when using SQL?
The order in which the columns are displayed
The order in which the expressions are sorted
The order in which the operators are returned
The order in which the expressions are evaluated and calculated (*)
All of the above
Quiz: Sorting Rows
1. What columns can be added to the following SELECT statement in its ORDER BY clause? (Choose Three)
SELECT first_name, last_name, salary, hire_date
FROM employees
WHERE department_id = 50
ORDER BY ?????;
last_name, first_name. (*)
All columns in the EMPLOYEES table. (*)
The table name, EMPLOYEES, which would then automatically sort by all columns in the table.
Any column in the EMPLOYEES table, any expression in the SELECT list or any ALIAS in the SELECT list. (*)
All the columns in the database.
2. Which of the following is true of the ORDER BY clause: (Choose Two)
Must be the last clause of the SQL statement (*)
Displays the fetched rows in no particular order
Defaults to a descending order (DESC)
Defaults to an ascending order (ASC) (*)
3. What clause must you place in a SQL statement to have your results sorted from highest to lowest salary?
ORDER BY salary ASC
ORDER BY salary DESC (*)
ORDER salary BY DESC
None, the database always sorts from highest to lowest on the salary column.
4. A column alias can be specified in an ORDER BY Clause. True or False?
True (*)
False
Quiz: Limit Rows Selected
1. Which example would limit the number of rows returned?
SELECT title FROM d_songs WHEN type_code = 88;
SELECT title FROM d_songs WHERE type_code = = 88;
SELECT title FROM d_songs WHERE type_code = 88; (*)
SELECT title FROM d_songs WHEN type_code = = 88;
2. Which of the following would be returned by this SELECT statement:
SELECT last_name, salary
FROM employees
WHERE salary <>
LAST_NAME SALARY
King 5000
LAST_NAME SALARY
Rajas 3500
LAST_NAME SALARY
Davies 3100
(*)
All of the above
3. To restrict the rows returned from an SQL Query, you should use the _____ clause:
SELECT
WHERE (*)
GROUP BY
CONDITION
All of the above
4. Which of the following statements will work?
SELECT first_name ||’ ‘||last_name NAME, department_id DEPARTMENT, salary*12 “ANNUAL SALARY”
FROM employees
WHERE name = ‘King’;
SELECT first_name ||’ ‘||last_name NAME, department_id DEPARTMENT, salary*12 “ANNUAL SALARY”
FROM employees
WHERE last_name = ‘King’;
(*)
SELECT first_name ||’ ‘||last_name NAME, department_id DEPARTMENT, salary*12 ‘ANNUAL SALARY’
FROM employees
WHERE last_name = ‘King’;
SELECT first_name ||’ ‘||last_name NAME, department_id DEPARTMENT, salary*12 ‘ANNUAL SALARY’
FROM employees
WHERE name = ‘King’;
5. Which query would give the following result?
LAST_NAME FIRST_NAME DEPARTMENT_ID
King Steven 90
SELECT last_name, first_name, department_id
FROM employees C
WHERE last_name = ‘KING’;
SELECT last_name, first_name, department_id
FROM employees
WHERE last_name = ‘King’;
(*)
SELECT last_name, first_name, department_id
FROM employees
WHERE last_name LIKE ‘k%’;
SELECT last_name, first_name, department_id
FROM employees
WHERE last_name LIKE ‘KING’;
6. Which of the following are true? (Choose Two)
Character strings are enclosed in double quotation marks
Date values are enclosed in single quotation marks (*)
Character values are not case-sensitive
Date values are format-sensitive (*)
7. How can you write not equal to in the WHERE-clause
!=
^=
<>
All of the above (*)
Quiz: Working with Columns, Characters, and Rows
1. The following is a valid SQL SELECT statement. True or False?
SELECT first_name || ‘ ‘ || last_name alias AS Employee_Name
FROM employees:
True
False (*)
2. In order to eliminate duplicate rows use the ________ keyword
FIRST_ONLY
DISTINCT (*)
SINGLES_ONLY
EXCLUSIVE
3. The structure of the table can be displayed with the _________ command:
Desc
Describe
Dis
A and B (*)
4. Which of the following is NOT BEING DONE in this SQL statement?
SELECT first_name || ‘ ‘ || last_name “Name”
FROM employees;
Concatenating first name, middle name and last name (*)
Putting a space between first name and last name
Selecting columns from the employees table
Using a column alias
5. The concatenation operator …
Brings together columns or character strings into other columns
Creates a resultant column that is a character expression
Is represented by two vertical bars ( || )
All of the above (*)
Quiz: Relational Database Technology
1. The following statements are true regarding tables in a RDBMS: (Choose Two)
A table is a logical object only. They cannot be created in a RDBMS.
A table holds all the data necessary about something in the real world, such as employees, invoices or customers. (*)
Tables contain fields, which can be found at the intersection of a row and a column. (*)
It is not possible to relate multiple tables within an RDBMS.
2. RDBMS stands for
Relational database manipulation system.
Relational database management system. (*)
Relational database mutilation system.
Relational database management style.
3. Once data has been created in a RDBMS, the ony way of getting it out again is by writing a Java or C program. No other languages can be used to access that data. True or False?
True
False (*)
4. The following table creation statement is valid. True or False?
CREATE TABLE country (
ID NUMBER(6) NOT NULL,
NAME VARCHAR2(30) NOT NULL,
LOC VARCHAR2(40),
REG_ID NUMBER,
NAME VARCHAR2(25))
True
False (*)
Quiz: Anatomy of a SQL Statement
1. The SQL SELECT statement is capable of:
Selection and protection
Selection and projection (*)
Projection and updating
None of the above
2. If you want to see just a subset of the columns in a table, you use what symbol?
&
%
*
None of the above, instead of using a symbol you name the columns you want to see the data for. (*)
3. The order of operator precedence is
/ + – *
* – + /
* / + – (*)
None of the above
4. If you want to see all columns of data in a table, you use what symbol?
&
%
$
* (*)
5. SELECT * FROM departments; is a:
Keyword
Statement (*)
Declaration
Strategy
6. What is a NULL value?
A perfect zero
A known value less than zero
A blank space
An unknown value (*)
Quiz: System Development Life Cycle
1. In which phases of the System Development Life Cycle will we need to use SQL as a language? (Choose Two)
Analysis
Transition (*)
Strategy
Build and Document (*)
2. The data model can be used to…
Communicate and group
Describe and specify
Analyze and copy
All of the Above (*)
3. During which phases of the System Development Life Cycle would you roll out the system to the users?
Build and Transition
Strategy and Analysis
Design and Production
Transition and Production (*)
Quiz: Basic Table Modifications
1. The SQL statement ALTER TABLE EMPLOYEES DROP COLUMN SALARY will delete all of the rows in the employees table. True or False?
True
False (*)
2. What will the following statement do to the employee table?
ALTER TABLE employees ADD (gender VARCHAR2(1))
Add a new row to the EMPLOYEES table
Rename a column in the EMPLOYEES table
Change the datatype of the GENDER column
Add a new column called GENDER to the EMPLOYEES table (*)
3. The f_customers table contains the following data:
ID Name Address City State Zip
1 Cole Bee 123 Main Street Orlando FL 32838
2 Zoe Twee 1009 Oliver Avenue Boston MA 02116
3 Sandra Lee 22 Main Street Tampa FL 32444
If you run the following statement,
DELETE FROM F_CUSTOMERS
WHERE STATE=’FL’;
how many rows will be left in the table?
0
1 (*)
2
3
Quiz: SQL Introduction: Querying the Database
1. What command can be added to a select statement to return a subset of the data?
WHERE (*)
WHEN
ALL
EVERYONE
2. What command retrieves data from the database?
ALTER
SELECT (*)
DESCRIBE
INSERT
3. What command do you use to add rows to a table
INSERT (*)
ADD
ADD_ROW
NEW_ROW
4. What command can be used to show information about the structure of a table?
ALTER
SELECT
DESCRIBE (*)
INSERT
5. Examine the follolowing SELECT statement.
SELECT *
FROM employees;
This statement will retrieve all the rows in the employees table. True or False?
True (*)
False
Quiz: Subtype Mapping
1. Which of the following are reasons you should consider when using a Subtype Implementation? (Choose Two)
When the common access paths for the subtypes are similar.
When the common access paths for the subtypes are different. (*)
Business functionality and business rules are similar between subtypes.
Most of the relationships are at the subtype level (*)
2. When mapping supertypes, relationships at the supertype level transform as usual. Relationships at subtype level are implemented as foreign keys, but the foreign key columns all become optional. True or False?
True (*)
False
3. When translating an arc relationship to a physical design, you must turn the arc relationships into foreign keys. What additional step must you take with the created foreign keys to ensure the exclusivity principle of arc relationships? (Assume that you are implementing an Exclusive Design) (Choose Two)
Make all relationships mandatory
Make all relationships optional (*)
Create an additional check constraint to verify that one foreign key is populated and the others are not (*)
All the above
4. The “Arc Implementation” is a synonym for what type of implementation?
Supertype Implementation
Subtype Implementation
Cascade Implementation
Supertype and Subtype Implementation (*)
Quiz: Relationship Mapping
1. Two entities A and B have an optional (A) to Mandatory (B) One-to-One relationship. When they are transformed, the Foreign Key(s) is placed on:
The table BS (*)
The Table AS
Nowhere, One-to-One are not transformed
Both tables As and Bs get a new column and a Foreign Key.
2. Relationships on an ERD can only be transformed into UIDs in the physical model? True or False?
True
False (*)
3. What do you create when you transform a many to many relationship from your ER diagram into a physical design?
Foreign key constraints
Intersection entity
Intersection table (*)
Primary key constraints
4. One-to-One relationships are transformed into Foreign Keys in the tables created at either end of that relationship? True or False?
True
False (*)
5. A barrred Relationship will result in a Foreign Key column that also is part of:
The Table Name
The Column Name
The Check Constraint
The Primary Key (*)
6. One-to-Many Optional to Mandatory becomes a _______________ on the Master table.
Mandatory Foreign Key
Nothing (There are no new columns created on the Master table) (*)
Optional Foreign Key
Primary Key
Quiz: Basic Mapping: The Transformation Process
1. In a physical data model, a relationship is represented as a:
Column
Primary Key
Unique Identifier
Foreign Key (*)
2. Why would this table name NOT work in an Oracle database?
2007_EMPLOYEES
Numbers cannot be incorporated into table names
Table names must start with an alphabetic character (*)
Underscores “_” are not allowed in table names
None of the above
3. The transformation from an ER diagram to a physical design involves changing terminology. Relationships in the ER diagram become __________ , and primary unique identifiers become ____________.
Foreign keys, primary keys (*)
Primary keys, foreign keys
Foreign keys, mandatory business rules
Foreign keys, optional business rules
4. The transformation from an ER diagram to a physical design involves changing terminology. Entities in the ER diagram become __________ , and attributes become ____________.
Columns, Tables
Tables, Columns (*)
Foreign Keys, Columns
Tables, Foreign Keys
5. In a physical data model, an entity becomes a _____________.
Attribute
Table (*)
Constraint
Column
6. Attributes become columns in a database table. True or False?
True (*)
False
7. In an Oracle database, why would the following table name not be allowed ‘EMPLOYEE JOBS’?
The database does not understand all capital letters
EMPLOYEE is a reserved word
JOBS is a reserved word
You cannot have spaces between words in a table name (*)
Quiz: Introduction to Relational Database Concepts
1. One or more columns in a primary key can be null. True or False?
True
False (*)
2. Foreign keys cannot be null when:
It is part of a primary key. (*)
It refers to another table.
It contains three or more columns.
3. A foreign key always refers to a primary key in the same table. True or False?
True
False (*)
4. The explanation below defines which constraint type:
A primary key must be unique, and no part of the primary key can be null.
Entity integrity. (*)
Referential integrity.
Column integrity.
User-defined integrity.
5. The explanation below defines which constraint type:
A column must contain only values consistent with the defined data format of the column.
Entity integrity.
Referential integrity.
Column integrity. (*)
User-defined integrity.
6. Column integrity refers to:
Columns always having values.
Columns always containing positive numbers.
Columns always containing values consistent with the defined data format. (*)
Columns always containing text data less than 255 characters.
7. The explanation below is an example of what constraint type:
The value in the dept_no column of the EMPLOYEES table must match a value in the dept_no column in the DEPARTMENTS table.
Entity integrity.
Referential integrity. (*)
Column integrity.
User-defined integrity.
8. Identify all of the correct statements that complete this sentence: A primary key is: (Choose Three)
A single column that uniquely identifies each row in a table. (*)
A set of columns that uniquely identifies each row in a table. (*)
A set of columns and keys in a single table that uniquely identifies each row in a single table. (*)
Only one column that cannot be null.
9. The explanation below is an example of what constraint type:
If the value in the balance column of the ACCOUNTS table is below 100, we must send a letter to the account owner which will require extra programming to enforce.
Entity integrity.
Referential integrity.
Column integrity.
User-defined integrity. (*)
10. A table does not have to have a primary key. True or False?
True (*)
False
Quiz: Generic Modeling
1. Generic models are generally less complex than a specific model. True or False?
True
False (*)
2. All data models MUST have some portions of the model modeled as a generic component. True or False?
True
False (*)
3. When you transform a specific model to be generic, which of the following statements are true? (Choose Two)
You tend to end up with fewer entities in the generic model than you had in the specific model. (*)
Either all or none of the original attributes make it into the generic model. (*)
You will always have more entities in a generic model than in the corresponding specific model.
None of the original specific model attributes are allowed in a generic model.
Test: Quiz: Drawing Conventions for Readability
1. You must make sure all entities of a proposed system can fit onto one diagram. It is not allowed to break up a data model into more than one diagram. True or False?
True
False (*)
2. It is a good idea to group your entities in a diagram according to the expected volumes. By grouping high volume entities together, the diagrams could become easier to read. True or False?
True (*)
False
3. Which of the following statements are true for ERD’s to enhance their readability. (Choose Two)
(Choose all correct answers)
There should be no crossing lines. (*)
All crows feet (Many-ends) of relationships should point the same way. (*)
There should be many crossing lines.
It does not matter which way the crows feet (many ends) point.
4. There are no formal rules for how to draw ERD’s. The most important thing is to make sure all entities, attributes and relationships are documented on diagram. The layout is not significant. True or False?
True
False (*)
Test: Quiz: Modeling Change: Price
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Modeling Change: Price
(Answer all questions in this section)
1. Why would you want to model a time component when designing a system that lets people buy bars of gold? Mark for Review
(1) Points
The price of gold fluctuates and for determining price, you need to know the time of purchase (*)
To allow the sales people to determine where the gold is coming from
You would not want to model this, it is not important
The Government of your country might want to be notified of this transaction.
2. Which of the following is a logical constraint that could result from considering how time impacts an example of data storage? Mark for Review
(1) Points
End Date must be before the Start Date.
ASSIGNMENT periods can overlap causing the database to crash.
An ASSIGNMENT may only refer to a COUNTRY that is valid at the Start Date of the ASSIGNMENT. (*)
Dates can be valued only with Time.
3. What is the function of logging or journaling in conceptual data models? Mark for Review
(1) Points
Allows you to track the history of attribute values, relationships and/or entire entities (*)
Gives a timestamp to all entities
Represents entities as time in the data model
Creates a fixed time for all events in a data model
4. You are doing a data model for a computer sales company, where the price goes down on a regular basis. If you want to allow them to modify the price and keep track of the changes, what is the best way to model this? Mark for Review
(1) Points
A. Create a product entity and a related price entity with start and end dates, and then let the users enter the new price whenever required.
B. Create a new item and a new price every day.
C. Use a price entity with a start and end date
D. Allow them to delete the item and enter a new one.
E. Both A and C (*)
Test: Quiz: Modeling Change: Time
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Modeling Change: Time
(Answer all questions in this section)
1. When you add the concept of time to your data model, you are: Mark for Review
(1) Points
Simplifying your model.
Adding complexity to your model. (*)
Just changing the model, but this does not change the complexity of it.
None of the above.
2. It is desirable to have an entity called DAY with a holiday attribute when you want to track special holidays in a payroll system. True or False? Mark for Review
(1) Points
True (*)
False
3. What is the benefit to the users of a system that includes "time," e.g. Start Date and End Date for Employees? Mark for Review
(1) Points
Increased usability and flexibility of a system; we can the trace e.g. the different managers an employee had over time. (*)
System becomes 100% unstable; allows users to log on and log off at will.
Users are able to create complex programs in support of this component.
Reporting becomes nearly impossible, users enjoy this.
4. How do you know when to use the different types of time in your design? Mark for Review
(1) Points
The rules are fixed and should be followed
It depends on the functional needs of the system (*)
You would first determine the existence of the concept of time and map it against the Greenwich Mean Time
Always model time, you can take it out later if it is not needed
5. Which of the following would be a logical constraint when modeling time for a country entity? Mark for Review
(1) Points
People have births and deaths in their countries that must be tracked by the system.
If you are doing a system for France or Germany, you would need security clearance.
Countries may need an end date in your system, because they can change fundamentally over time, e.g. Yugoslavia. (*)
You need a constant record of countries, because they are still countries, even if leadership changes over time, e.g. France, USA and most other countries.
6. Modeling historical data produces efficient ways for a business to operate such as: Mark for Review
(1) Points
Modeling historical data does not help a business.
Providing valuable information via reports to management . (*)
Keeping track of holiday dates.
Employees can work in two time zones.
7. If you are tracking employment dates for an employee, do you need to have an "End Date" attribute? Mark for Review
(1) Points
Yes, because you always need an end date when you have a start date
No, because an end date is usually redundant
Yes, if the company wants to track employee information, like multiple start and end dates (*)
No, not if the company likes the employee
Test: Quiz: What is a Consultant
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
What is a Consultant
(Answer all questions in this section)
1. Only Consultants can develop new data models for a company, they are mandatory, so companies must find them and hire them. True or False? Mark for Review
(1) Points
True
False (*)
2. Which of the following skills are required for Consultants. (Choose Two) Mark for Review
(1) Points
(Choose all correct answers)
Communication skills (*)
Excellent drawing skills
Must be able to speak at least two languages fluently, preferably four or more
Team-working skills (*)
3. How does the dictionary define "consultant"? Mark for Review
(1) Points
A person who knows everything
One responsible for knowing everything
One who gives expert or professional advice (*)
None of the Above
Test: Quiz: Overcoming the Fear Factor
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Overcoming the Fear Factor
(Answer all questions in this section)
1. When you are involved in a group presentation, your group should practice before hand and agree on who presents the various parts. You should all be involved somehow. True or False? Mark for Review
(1) Points
True (*)
False
2. Your apperance at a presentation is not important, you should just show up and give the presentation in whatever clothes makes you comfortable. So feel free to wear Jeans and old T-Shirts etc. Being comfortable is more important than anything else. True or False? Mark for Review
(1) Points
True
False (*)
3. Which of the following is a valid technique for effective public speaking? Mark for Review
(1) Points
Making eye contact
Using familiar words when communicating technical information
Being enthusiastic
All of the Above (*)
Test: Quiz: Hierarchies and Recursive Relationships
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Hierarchies and Recursive Relationships
(Answer all questions in this section)
1. Which of the following would be a good Unique Identifier for its Entity? (Choose Two) Mark for Review
(1) Points
(Choose all correct answers)
Identification Number for Person (*)
Birthdate for Baby Which Includes Hour, Minute, and Seconds (*)
Order date for Order
Vehicle Type Number for Car
2. A relationship can be both recursive and hierachal at the same time. True or False? Mark for Review
(1) Points
True
False (*)
3. A recursive rationship should not be part of a UID. True or False? Mark for Review
(1) Points
True (*)
False
4. In this simple diagram, what comprises the unique identifier for the student class entity?
Mark for Review
(1) Points
student id and class id
student id, class id and course id
course id
student id and course id (*)
Test: Quiz: Modeling Historical Data
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Modeling Historical Data
(Answer all questions in this section)
1. Historical data should always be kept. True or False? Mark for Review
(1) Points
True
False (*)
2. Modeling historical data can produce a unique identifier that includes a date. True or False? Mark for Review
(1) Points
True (*)
False
3. Which of the following scenarios should be modeled so that historical data is kept? (Choose two) Mark for Review
(1) Points
(Choose all correct answers)
LIBRARY and BOOK (*)
STUDENT and AGE
STUDENT and GRADE (*)
LIBRARY and NUMBER OF STAFF
4. Audit trail attributes cannot be placed in the entities they are auditing, they must be placed in separate, new entities, created just for that purpose. True or False? Mark for Review
(1) Points
True
False (*)
Test: Quiz: Arcs
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Arcs
(Answer all questions in this section)
1. Which of the following can be added to a relationship? Mark for Review
(1) Points
an attribute
an arc can be assigned (*)
a composite attribute
an optional attribute can be created
2. Secondary UID's are Mark for Review
(1) Points
not permitted in data modeling
mandatory in data modeling
useful as an alternative means identifying instances of an entity (*)
always comprised of numbers
3. Which of the following would best be represented by an arc? Mark for Review
(1) Points
STUDENT (senior, junior)
STUDENT (graduating, non-graduating)
STUDENT (will-attend-university, will-not-attend-university)
STUDENT ( University, Trade School) (*)
4. If the entity CD has the attributes: #number, *title, *producer, *year, o store name, o store address, this entity is in 3rd Normal Form ("no non-UID attribute can be dependent on another non-UID attribute). True or False? Mark for Review
(1) Points
True
False (*)
5. Which of the following is the definition for Third Normal Form? Mark for Review
(1) Points
All attributes are single valued
An attribute must be dependent upon entity's entire unique identifier
No non-UID attribute can be dependent on another non-UID attribute (*)
All attributes are uniquely doubled and independent
6. To visually represent exclusivity between two or more relationships in an ERD you would most likely use an ________. Mark for Review
(1) Points
Arc (*)
UID
Subtype
Supertype
7. This diagram could also be expressed as a supertype/subtype construction. True or False?
Mark for Review
(1) Points
True
False (*)
8. All parts of a UID are mandatory. True or False? Mark for Review
(1) Points
True (*)
False
Test: Quiz: Third Normal Form
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Third Normal Form
(Answer all questions in this section)
1. As a database designer it is your job to store data in only one place and the best place. True or False? Mark for Review
(1) Points
True (*)
False
2. Examine the following Entity and decide which sets of attributes breaks the 3rd Normal Form rule: (Choose Two)
ENTITY: TRAIN (SYNONYM: ROLLING STOCK)
ATTRIBUTES:
TRAIN ID
MAKE
MODEL
DRIVER NAME
DEPARTURE STATION
NUMBER OF CARRIAGES
NUMBER OF SEATS
DATE OF MANUFACTURE
Mark for Review
(1) Points
(Choose all correct answers)
TRAIN ID, MAKE
DEPARTURE STATION, DRIVER NAME (*)
NUMBER OF CARRIAGES, NUMBER OF SEATS (*)
MODEL, DATE OF MANUFACTURE
3. No databases in the world is ever truly on 3rd Normal Form. Everyone always stops after 2nd Normal Form. True or False? Mark for Review
(1) Points
True
False (*)
Test: Quiz: Second Normal Form
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Second Normal Form
(Answer all questions in this section)
1. What is the rule of Second Normal Form? Mark for Review
(1) Points
All non-UID attributes must be dependent upon the entire UID (*)
Some non-UID attributes can be dependent on the entire UID
No non-UID attributes can be dependent on any part of the UID
None of the Above
2. Examine the following entity and decide which attribute breaks the 2nd Normal Form rule:
ENTITY: CLASS
ATTRIBUTES:
CLASS ID
DURATION
SUBJECT
TEACHER NAME AND ADDRESS
Mark for Review
(1) Points
CLASS ID
DURATION
SUBJECT
TEACHER NAME AND ADDRESS (*)
3. All instances of the subtypes must be an instance of the supertype. Mark for Review
(1) Points
True (*)
False
4. Not all instances of the supertype are instances of one of the subtypes. Mark for Review
(1) Points
True
False (*)
5. A supertype should have at least two subtypes. Mark for Review
(1) Points
True (*)
False
6. An entity can be on 2nd Normal Form even if it has repeated values. True or False? Mark for Review
(1) Points
True
False (*)
Test: Quiz: Normalization and First Normal Form
Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Normalization and First Normal Form
(Answer all questions in this section)
1. When data is stored in more than one place in a database, the database violates the rules of ___________. Mark for Review
(1) Points
Normalization (*)
Replication
Normalcy
Decency
2. When all attributes are single-valued, the database model is said to conform to: Mark for Review
(1) Points
1st Normal Form (*)
2nd Normal Form
3rd Normal Form
4th Normal Form
3. An entity can have repeated values and still be in 1st Normal Form. True or False? Mark for Review
(1) Points
True
False (*)
4. The following entity is on 1st normal form: True or False?
ENTITY: VEHICLE
ATTRIBUTES:
REGISTRATION
MAKE
MODEL
COLOR
DRIVER
PASSENGER 1
PASSENGER 2
PASSENGER 3
Mark for Review
(1) Points
True
False (*)
Test: Quiz: Artificial, Composite and Secondary UIDs
duminică, 15 noiembrie 2009
Test: Quiz: Resolving Many to Many Relationships
1. If an intersection entity is formed that contains no attributes of its own, its uniqueness may be modeled by Mark for Review
(1) Points
Creating new attributes.
Barring the relationships to the original entities. (*)
Placing the UID attributes from the original entities into the intersection entity.
None of the above.
2. When you resolve a M-M by creating an intersection entity, this new entity will always inherit: Mark for Review
(1) Points
The attributes of both related entities.
A relationship to each entity from the original M-M. (*)
The UID's from the entities in the original M-M.
Nothing is inherited from the original entities and relationship.
3. Many-to-Many relationships are perfectly acceptable in a finished ERD. There is no need to do any more work on them. True or False? Mark for Review
(1) Points
True
False (*)
Test: Quiz: Relationship Types
1. What uncommon relationship is described by the statements: "Each LINE must consist of many POINTS and each POINT must be a part of many LINES" Mark for Review
(1) Points
One to Many Optional
One to Many Mandatory
Many to Many Optional
Many to Many Mandatory (*)
2. If the same relationship is represented twice in an Entity Relationship Model, it is said to be: Mark for Review
(1) Points
Replicated
Removable
Redundant (*)
Resourceful
3. When are relationships unnecessary? Mark for Review
(1) Points
When you can derive the relationship from other relationships in the model (*)
When they have the same visual structure but different meaning
When the information does not relate to the model
When the relationships connect 2 entities and they each have distinct meanings
4. Which of the following pairs of entities is most likely to be modeled as a M:M relationship? (Choose Two) Mark for Review
(1) Points
(Choose all correct answers)
STUDENT and CLASS (*)
TREE and SEEDLING
PHONE NUMBER and SIM CARD
CAR and DRIVER (*)
5. When resolving an M:M relationship, the new relationships will always be __________ on the many side. Mark for Review
(1) Points
optional
recursive
mandatory (*)
redundant
6. Which of the following are relationship types? (Choose Two) Mark for Review
(1) Points
(Choose all correct answers)
One to Some
Many to Many (*)
One to Many (*)
One to Another
7. Many to many relationships between entities usually hide what? Mark for Review
(1) Points
Another relationship
Another entity (*)
More attributes
Uniqueness
Test: Quiz: Relationship Transferability
1. A non-transferable relationship is represented by which of the following symbols? Mark for Review
(1) Points
Heart
Diamond (*)
Circle
Triangle
2. Non-transferable relationships can only be mandatory, not optional. True or False? Mark for Review
(1) Points
True (*)
False
3. If a relationship can be moved between instances of the entities it connects, it is said to be: Mark for Review
(1) Points
Implicit
Transferrable (*)
Committed
Recursive
Test: Quiz: Documenting Business Rules
1. Why is it important to identify and document business rules? Mark for Review
(1) Points
It allows you to create your data model, then check for accuracy. (*)
It allows you to improve the client's business.
It ensures that the data model will automate all manual processes.
None of the above
2. A business rule such as "All accounts must be paid in full within 10 days of billing" is best enforced by: Mark for Review
(1) Points
Making the payment attribute mandatory.
Making the relationship between CUSTOMER and PAYMENT fully mandatory and 1:1 on both sides.
Creating a message to be printed on every bill that reminds the customer to pay within ten days.
Hiring a programmer to create additional programming code to identify and report accounts past due. (*)
3. How should you handle constraints that cannot be modeled on an ER diagram? Mark for Review
(1) Points
Always let the network architect handle them
List them on a separate document to be handled programmatically (*)
Explain them to the users so they can enforce them
All constraints must be modeled and shown on the ER diagram
4. Which of the following is an example of a structural business rule? Mark for Review
(1) Points
All employees must belong to at least one department. (*)
Buildings to be purchased by the business must be current with earthquake building code.
All overdue payments will have an added 10 % late fee.
All products will have a selling price no less than 30 % greater than wholesale.
5. Only managers can approve travel requests is an example of which of the following? Mark for Review
(1) Points
A structural business rule.
A mandatory business rule.
A procedural business rule. (*)
An optional business rule.
6. How would you model a business rule that states that on a studentメs birthday, they do not have to attend their classes? Mark for Review
(1) Points
Use a supertype
Use a subtype
Make the attribute Birthdate mandatory
You cannot model this. You need to document it (*)
7. Business rules are important to data modelers because: Mark for Review
(1) Points
A. They capture all of the needs, processes and required functionality of the business. (*)
B. They are easily implemented in the ERD diagram.
C. The data modeler must focus on structural rules, because they are easily represented diagrammatically and eliminate other rules that involve extra procedures or programming.
D. Both A and C are true.
Test: Quiz: Supertypes and Subtypes
1. All instances of the subtypes must be an instance of the supertype. True or False? Mark for Review
(1) Points
True (*)
False
2. Which of the following is true about supertypes and subtypes? Mark for Review
(1) Points
Instances that belong to two subtypes of the same supertype may be modeled as a one-to-one relationship between the two subtypes
Subtypes inherit the relationships and attributes of the supertype (*)
Subtypes may have no more than 2 levels of nesting
Supertype and subtype entities must be mutually exclusive
3. When creating entities it is important to remember all of the following: (Choose Two) Mark for Review
(1) Points
(Choose all correct answers)
Create a formal description. (*)
Include attributes. (*)
Do not use synonyms.
Do use reserved words.
4. All instances of the supertype are also instances of one of the subtypes. True or False? Mark for Review
(1) Points
True (*)
False
5. Which of the following is a TRUE statement about the diagram below?
Mark for Review
(1) Points
Every Z is either an A or a B
Every B is a Z
Every A is a Z
Every A is a B (*)
6. The "Other" subtype is best used: Mark for Review
(1) Points
For instances that belong to the supertype and at least one other subtype.
For a subtype that does not have any of the same attributes as the supertype to which it belongs.
As an extra subtype to ensure that all instances of subtypes are mutually exclusive and complete. By having an "Other" subtype, all instances of the Supertype will be of one subtype type. (*)
You should never have a subtype called Other.
7. Which of the following is the best scenario for using supertype/subtype entities: Mark for Review
(1) Points
A pet store that sells small animals, because they each need different size cages and food.
An ice cream store that sells ice cream in sugar cones and regular cones.
A grocery store that gives customers a choice of plastic or paper bags.
A vehicle dealership that sells cars, trucks and boats on trailers. (*)
8. A subtype can have a relationship not shared by the supertype. True or False? Mark for Review
(1) Points
True (*)
False
9. A supertype should have at least two subtypes. True or False? Mark for Review
(1) Points
True (*)
False
10. Which of the following are valid formats for an attribute? (Choose Two) Mark for Review
(1) Points
(Choose all correct answers)
Character string (*)
Decimal
Number (*)
HEX
Test: Quiz: Matrix Diagrams
1. A Matrix Diagram will help you with all of the following except: Mark for Review
(1) Points
Defining Relationships Between Entities
Identifying Entities
Defining Instances of Entities (*)
Naming Relationships
2. Creating a Matrix Diagram is mandatory when doing Data Modeling. True or False? Mark for Review
(1) Points
True
False (*)
3. Matrix Diagrams helps verify you have identified all possible relationships between your existing entities. True or False? Mark for Review
(1) Points
True (*)
False