Normalization Basics – 1NF 2NF and 3NF

Description of Normalization

Normalization is the process of organizing data in a database. This includes creating tables and establishing relationships between those tables according to rules designed both to protect the data and to make the database more flexible by eliminating redundancy and inconsistent dependency.

Redundant data wastes disk space and creates maintenance problems. If data that exists in more than one place must be changed, the data must be changed in exactly the same way in all locations. A customer address change is much easier to implement if that data is stored only in the Customers table and nowhere else in the database.

What is an “inconsistent dependency”? While it is intuitive for a user to look in the Customers table for the address of a particular customer, it may not make sense to look there for the salary of the employee who calls on that customer. The employee’s salary is related to, or dependent on, the employee and thus should be moved to the Employees table. Inconsistent dependencies can make data difficult to access because the path to find the data may be missing or broken.

There are a few rules for database normalization. Each rule is called a “normal form.” If the first rule is observed, the database is said to be in “first normal form.” If the first three rules are observed, the database is considered to be in “third normal form.” Although other levels of normalization are possible, third normal form is considered the highest level necessary for most applications.

As with many formal rules and specifications, real world scenarios do not always allow for perfect compliance. In general, normalization requires additional tables and some customers find this cumbersome. If you decide to violate one of the first three rules of normalization, make sure that your application anticipates any problems that could occur, such as redundant data and inconsistent dependencies.

The following descriptions include examples.

First Normal Form

•	Eliminate repeating groups in individual tables.
•	Create a separate table for each set of related data.
•	Identify each set of related data with a primary key.

Do not use multiple fields in a single table to store similar data. For example, to track an inventory item that may come from two possible sources, an inventory record may contain fields for Vendor Code 1 and Vendor Code 2.

What happens when you add a third vendor? Adding a field is not the answer; it requires program and table modifications and does not smoothly accommodate a dynamic number of vendors. Instead, place all vendor information in a separate table called Vendors, then link inventory to vendors with an item number key, or vendors to inventory with a vendor code key.

Second Normal Form

•	Create separate tables for sets of values that apply to multiple records.
•	Relate these tables with a foreign key.

Records should not depend on anything other than a table’s primary key (a compound key, if necessary). For example, consider a customer’s address in an accounting system. The address is needed by the Customers table, but also by the Orders, Shipping, Invoices, Accounts Receivable, and Collections tables. Instead of storing the customer’s address as a separate entry in each of these tables, store it in one place, either in the Customers table or in a separate Addresses table.

Third Normal Form

•	Eliminate fields that do not depend on the key.

Values in a record that are not part of that record’s key do not belong in the table. In general, any time the contents of a group of fields may apply to more than a single record in the table, consider placing those fields in a separate table.

For example, in an Employee Recruitment table, a candidate’s university name and address may be included. But you need a complete list of universities for group mailings. If university information is stored in the Candidates table, there is no way to list universities with no current candidates. Create a separate Universities table and link it to the Candidates table with a university code key.

EXCEPTION: Adhering to the third normal form, while theoretically desirable, is not always practical. If you have a Customers table and you want to eliminate all possible interfield dependencies, you must create separate tables for cities, ZIP codes, sales representatives, customer classes, and any other factor that may be duplicated in multiple records. In theory, normalization is worth pursing. However, many small tables may degrade performance or exceed open file and memory capacities.

It may be more feasible to apply third normal form only to data that changes frequently. If some dependent fields remain, design your application to require the user to verify all related fields when any one is changed.

Normalizing an Example Table

loadTOCNode(2, ‘moreinformation’); These steps demonstrate the process of normalizing a fictitious student table.

1.	Unnormalized table: Student# Advisor Adv-Room Class1 Class2 Class3 1022 Jones 412 101-07 143-01 159-02 4123 Smith 216 201-01 211-02 214-01
2.	First Normal Form: No Repeating Groups Tables should have only two dimensions. Since one student has several classes, these classes should be listed in a separate table. Fields Class1, Class2, and Class3 in the above records are indications of design trouble. Spreadsheets often use the third dimension, but tables should not. Another way to look at this problem is with a one-to-many relationship, do not put the one side and the many side in the same table. Instead, create another table in first normal form by eliminating the repeating group (Class#), as shown below: Student# Advisor Adv-Room Class# 1022 Jones 412 101-07 1022 Jones 412 143-01 1022 Jones 412 159-02 4123 Smith 216 201-01 4123 Smith 216 211-02 4123 Smith 216 214-01
3.	Second Normal Form: Eliminate Redundant Data Note the multiple Class# values for each Student# value in the above table. Class# is not functionally dependent on Student# (primary key), so this relationship is not in second normal form. The following two tables demonstrate second normal form: Students: Student# Advisor Adv-Room 1022 Jones 412 4123 Smith 216 Registration: Student# Class# 1022 101-07 1022 143-01 1022 159-02 4123 201-01 4123 211-02 4123 214-01
4.	In the last example, Adv-Room (the advisor’s office number) is functionally dependent on the Advisor attribute. The solution is to move that attribute from the Students table to the Faculty table, as shown below: Students: Student# Advisor 1022 Jones 4123 Smith Faculty: Name Room Dept Jones 412 42 Smith 216 42

Difference between require, require_once, include and include_once

All these functions require, require_once, include and include_once are used to include the files in the php page but there is slight difference between these functions.

Difference between require, require_once, include, include_once
Difference between require and include is that if the file you want to include is not found then include function give you warning and executes the remaining code in of php page where you write the include function. While require gives you fatal error if the file you want to include is not found and the remaining code of the php page will not execute.

If you have many functions in the php page then you may use require_once or include_once. There functions only includes the file only once in the php page. If you use include or require then may be you accidentally add two times include file so it is good to use require_once or include_once which will include your file only once in php page. Difference between require_once and include_onceis same as the difference between require and include.

Different types of errors in PHP

Here are three basic types of runtime errors in PHP:

1. Notices: These are trivial, non-critical errors that PHP encounters while executing a script – for example, accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all – although you can change this default behavior.

2. Warnings: These are more serious errors – for example, attempting to include() a file which does not exist. By default, these errors are displayed to the user, but they do not result in script termination.

3. Fatal errors: These are critical errors – for example, instantiating an object of a non-existent class, or calling a non-existent function. These errors cause the immediate termination of the script, and PHP’s default behavior is to display them to the user when they take place.

Difference between mysql_connect() and mysql_pconnect()

mysql_connect() and mysql_pconnect() both are working for database connection but with little difference. In mysql_pconnect(), ‘p’ stands for persistance connection.

When we are using mysql_connect() function, every time it is opening and closing the database connection, depending on the request .

But in case of mysql_pconnect() function,
First, when connecting, the function would try to find a (persistent) connection that’s already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection.
Second, the connection to the SQL server will not be closed when the execution of the script ends. Instead, the connection will remain open for future use (mysql_close() will not close connection established by mysql_pconnect()).

mysql_pconncet() is useful when you have a lot of traffice on your site. At that time for every request it will not open a connection but will take it from the pool. This will increase the efficiency of your site. But for general use mysql_connect() is best.

I think this is a very imp concept in case of Database Connectivity.

MySQL interview questions

1. What is DDL, DML and DCL? – If you look at the large variety of SQL commands, they can be divided into three large subgroups. Data Definition Language deals with database schemas and descriptions of how the data should reside in the database, therefore language statements like CREATE TABLE or ALTER TABLE belong to DDL. DML deals with data manipulation, and therefore includes most common SQL statements such SELECT, INSERT, etc. Data Control Language includes commands such as GRANT, and mostly concerns with rights, permissions and other controls of the database system.

2. How do you get the number of rows affected by query? – SELECT COUNT (user_id) FROM users would only return the number of user_id’s.

3. If the value in the column is repeatable, how do you find out the unique values? – Use DISTINCT in the query, such as SELECT DISTINCT user_firstname FROM users; You can also ask for a number of distinct values by saying SELECT COUNT (DISTINCT user_firstname) FROM users;

4. How do you return the a hundred books starting from 25th? – SELECT book_title FROM books LIMIT 25, 100. The first number in LIMIT is the offset, the second is the number.

5. You wrote a search engine that should retrieve 10 results at a time, but at the same time you’d like to know how many rows there’re total. How do you display that to the user? – SELECT SQL_CALC_FOUND_ROWS page_title FROM web_pages LIMIT 1,10; SELECT FOUND_ROWS(); The second query (not that COUNT() is never used) will tell you how many results there’re total, so you can display a phrase “Found 13,450,600 results, displaying 1-10”. Note that FOUND_ROWS does not pay attention to the LIMITs you specified and always returns the total number of rows affected by query.

6. How would you write a query to select all teams that won either 2, 4, 6 or 8 games? – SELECT team_name FROM teams WHERE team_won IN (2, 4, 6, 8 )

7. How would you select all the users, whose phone number is null? – SELECT user_name FROM users WHERE ISNULL(user_phonenumber);

8. What does this query mean: SELECT user_name, user_isp FROM users LEFT JOIN isps USING (user_id) – It’s equivalent to saying SELECT user_name, user_isp FROM users LEFT JOIN isps WHERE users.user_id=isps.user_id

9. How do you find out which auto increment was assigned on the last insert? – SELECT LAST_INSERT_ID() will return the last value assigned by the auto_increment function. Note that you don’t have to specify the table name.

10. What does –i-am-a-dummy flag to do when starting MySQL? – Makes the MySQL engine refuse UPDATE and DELETE commands where the WHERE clause is not present.

11. On executing the DELETE statement I keep getting the error about foreign key constraint failing. What do I do? – What it means is that so of the data that you’re trying to delete is still alive in another table. Like if you have a table for universities and a table for students, which contains the ID of the university they go to, running a delete on a university table will fail if the students table still contains people enrolled at that university. Proper way to do it would be to delete the offending data first, and then delete the university in question. Quick way would involve running SET foreign_key_checks=0 before the DELETE command, and setting the parameter back to 1 after the DELETE is done. If your foreign key was formulated with ON DELETE CASCADE, the data in dependent tables will be removed automatically.

12. When would you use ORDER BY in DELETE statement? – When you’re not deleting by row ID. Such as in DELETE FROM techinterviews_com_questions ORDER BY timestamp LIMIT 1. This will delete the most recently posted question in the table techinterviews_com_questions.

13. How can you see all indexes defined for a table? – SHOW INDEX FROM techinterviews_questions;

14. How would you change a column from VARCHAR(10) to VARCHAR(50)? – ALTER TABLE techinterviews_questions CHANGE techinterviews_content techinterviews_CONTENT VARCHAR(50).

15. How would you delete a column? – ALTER TABLE techinterviews_answers DROP answer_user_id.

16. How would you change a table to InnoDB? – ALTER TABLE techinterviews_questions ENGINE innodb;

17. When you create a table, and then run SHOW CREATE TABLE on it, you occasionally get different results than what you typed in. What does MySQL modify in your newly created tables? –
1. VARCHARs with length less than 4 become CHARs
2. CHARs with length more than 3 become VARCHARs.
3. NOT NULL gets added to the columns declared as PRIMARY KEYs
4. Default values such as NULL are specified for each column

18. How do I find out all databases starting with ‘tech’ to which I have access to? – SHOW DATABASES LIKE ‘tech%’;

19. How do you concatenate strings in MySQL? – CONCAT (string1, string2, string3)

20. How do you get a portion of a string? – SELECT SUBSTR(title, 1, 10) from techinterviews_questions;

21. What’s the difference between CHAR_LENGTH and LENGTH? – The first is, naturally, the character count. The second is byte count. For the Latin characters the numbers are the same, but they’re not the same for Unicode and other encodings.

22. How do you convert a string to UTF-8? – SELECT (techinterviews_question USING utf8);

23. What do % and _ mean inside LIKE statement? – % corresponds to 0 or more characters, _ is exactly one character.

24. What does + mean in REGEXP? – At least one character. Appendix G. Regular Expressions from MySQL manual is worth perusing before the interview.

25. How do you get the month from a timestamp? – SELECT MONTH(techinterviews_timestamp) from techinterviews_questions;

26. How do you offload the time/date handling to MySQL? – SELECT DATE_FORMAT(techinterviews_timestamp, ‘%Y-%m-%d’) from techinterviews_questions; A similar TIME_FORMAT function deals with time.

27. How do you add three minutes to a date? – ADDDATE(techinterviews_publication_date, INTERVAL 3 MINUTE)

28. What’s the difference between Unix timestamps and MySQL timestamps? – Internally Unix timestamps are stored as 32-bit integers, while MySQL timestamps are stored in a similar manner, but represented in readable YYYY-MM-DD HH:MM:SS format.

29. How do you convert between Unix timestamps and MySQL timestamps? – UNIX_TIMESTAMP converts from MySQL timestamp to Unix timestamp, FROM_UNIXTIME converts from Unix timestamp to MySQL timestamp.

30. What are ENUMs used for in MySQL? – You can limit the possible values that go into the table. CREATE TABLE months (month ENUM ‘January’, ‘February’, ‘March’,…); INSERT months VALUES (’April’);

31. How are ENUMs and SETs represented internally? – As unique integers representing the powers of two, due to storage optimizations.

What’s the difference between LEFT, RIGHT, INNER, OUTER, JOIN?

What’s the difference between LEFT, RIGHT, INNER, OUTER, JOIN?

The difference is in the way tables are joined if there are no common records.
JOIN is same as INNER JOIN and means to only show records common to both tables. Whether the records are common is determined by the fields in join clause. For example:

FROM t1
JOIN t2 on t1.ID = t2.ID

means show only records where the same ID value exists in both tables.
LEFT JOIN is same as LEFT OUTER JOIN and means to show all records from left table (i.e. the one that precedes in SQL statement) regardless of the existance of matching records in the right table.
RIGHT JOIN is same as RIGHT OUTER JOIN and means opposite of LEFT JOIN, i.e. shows all records from the second (right) table and only matching records from first (left) table.

Affirmations: Why Are They So Powerful?

Life

An affirmation is defined as something declared to be true; a positive statement or judgment.

Affirmations affirm what is going on inside your mind and your heart.

The garden of our life is developed through the planting of seeds that flow from our mouth on a daily basis.

If you respond to the state of your health, wealth and love life with negative phrases you will end up with a weedy patch for a life.

The good book reveals to us clearly that ‘life and death are in the power of the tongue.’

So to ensure that life is springing up in your garden (life), begin to speak the following phrases about:

* Your health
* Your wealth
* Your love

Here are those that I speak, and I trust that they will add great value to your life as you participate.
My Health Affirmations

* Health is my portion.
* I am energetic and enthusiastic.
* My body heals fast.
* Peace is my portion.
* No matter what has been suffered by my parents health wise, I am healthy, whole and terrific.
* Good health is mine to possess.
* My mind is brimming with healthy thoughts.
* I have a sound mind and body.
* I am well and have ‘well’ days.
* I treat my body as my temple.
* I move freely and forward.
* I treat my body with respect by feeding it healthy food, drinking healthy fluids, and exercising it regularly.

My Wealth Affirmations

* I deserve to have money in the bank.
* My income increases.
* I have an excellent credit rating.
* I am a wise spender.
* I have as much money as I can receive.
* I prosper financially.
* Bills are met with joy as I pay them on time.
* I save and invest out of every dollar I earn.
* I give at least 10% of everything I earn as my way of saying thank you for the 100% received.
* My income is without limit.
* I am creative when it comes to handling money.
* I am financially literate.

My Love Affirmations

* I love me and am secure with who I am.
* Love is forever.
* Love liberates me.
* To be in love is to be safe.
* My lover is my equal.
* By taking care of myself I take care of our love.
* I overcome jealousy by developing my own self-esteem.
* People love me for who I am.
* I deserve to be loved.
* I will develop my own love pattern, not the one set by my parents or my peers.
* Loving both others and myself gets better every day.
* The more I open myself up to loving and being loved the safer I feel.
* My lover and I respect each other and the decisions we make.
* My loving relationships are long lasting.

So go forth and speak these affirmations each and every day. Be prepared for a miracle.

11 Must Read Life Lessons From John Lennon

“For those of you in the cheap seats I’d like ya to clap your hands to this one; the rest of you can just rattle your jewelery!” John Lennon

I remember hearing ‘Hey Jude’ blaring from the speakers at school when I was a young boy. I was as much caught up in Beatle-mania as the next person. The ‘Fab Four’ totally turned the music world upside down with their vast array of melodies, clever lyrics and singable tunes.

They were dynamic, controversial, trendsetters, radicals, confrontational plus a whole lot more.

But even though I love the cheekiness – as represented in the above quote – of John Lennon, there is so much more that he shared with the world apart from his music. Therein lies a depth of wisdom that I would like to expand upon.

So let us explore together yet another side of the man that encouraged us all to ‘Imagine’.

1.”Life is what happens to you while you’re busy making other plans.”

It has been written that if you fail to plan, you plan to fail. Blink and twenty years will pass you by. Life is never a direct route. It weaves. It twists. It turns. But if you have a goal, a dream or a plan in place, it acts as a compass that keeps you on track, no matter what detours need to be taken along the way.

2. “Time you enjoy wasting, was not wasted.”

Nothing is ever wasted. I experienced nearly 26 years in my life that I call the ‘lost years’, and yet, even though my true identity was lost during that period, the lessons learnt were invaluable. Those years have supplied me with stories that I can now tell to help others to enjoy and prosper from their uniqueness.

3. “It doesn’t matter how long my hair is or what colour my skin is or whether I’m a woman or a man.”

Success is not restricted to culture, gender or heritage. Successful people rise up from every conceivable starting point. So we can never use our state of being as an excuse for never achieving great things. One person with a dream, and a willingness to do whatever it takes to achieve that dream, makes it a level playing field.

4. “A dream you dream alone is only a dream. A dream you dream together is reality.”

Dreams are no fun if you keep them to yourself. Dreams are to be shared. Dreams fulfilled are to be enjoyed by all. Whenever I succeed I celebrate it with my family and my friends. I get the greatest satisfaction from the spin-off of my successes and how they positively impact those whom I love.

5. “Reality leaves a lot to the imagination.”

Reality plus a sprinkle of imagination turns that which seems impossible into something that is possible. If you can imagine it, and you can believe it, you can achieve it. Dare to be as a child once again and imagine by asking yourself the question, ‘What if?’ Then go do.

6. “If someone thinks that love and peace is a cliché that must have been left behind in the Sixties, that’s his problem. Love and peace are eternal.”

To love and to be loved would have to be the greatest thing that I have ever experienced. In my darkest hours it has been the love shown to me that has sustained me and strengthened my resolve to press on.

And then there is peace. Solitude and the practice of solitude have constantly filled me with peace. It is the eye in the storm. It is the rock that stands firm. Peace has sustained me and refreshed me. And it is in this place that definitive and life changing decisions have been made to move me forward in life.

7. “I get by with a little help from my friends.”

Not one of us can do it alone. Without friends, and the support of friends, we live in a desert. For friends are the oases. Friends are the refreshing. Friends lift us up when we are down. Friends believe in us when no-one else does. Friends are there in fair weather, and there when storms rage. Friends know when to speak and when to keep silent. Friends for life.

8. “You don’t need anybody to tell you who you are or what you are. You are what you are!”

Stop listening to what others say you are. You are what you are, and the older you get the more knowledgeable you need to become of who you really are. This is your road of self discovery. This is the unveiling of your uniqueness. This is the birth of self-pride – a healthy pride that is proud of what you have been created to be and to do. Listen to your inner voice and stand up tall knowing who you are.

9. “Count your age by friends, not years. Count your life by smiles, not tears.”

Joy. Happiness. Companionship. Define your life by the company that you keep and by the goodness that you can deposit into the lives of those around you. How do you measure the effectiveness of your life? Make it much more than what you can acquire. Measure it by what you can give.

10. “There’s nowhere you can be that isn’t where you’re meant to be…”

Nothing happens by accident. There is an eternal plan for each of us, and even what appears to be the greatest mistake will in retrospect be the perfect piece of stitching embroidered into the fabric of your life. Someone once showed me the back of an embroidered piece of cloth. On the back it appeared as a tangled mess. But by turning it over a beautiful piece of handiwork was revealed. So too our lives.

11. “One thing you can’t hide – is when you’re crippled inside.”

Angry people are angry with themselves. Unfriendly people don’t like themselves. How people act clearly reveals what is going on in the inside of their minds and hearts. People who love themselves have no difficulty in loving others. People who have no problem in forgiving others have forgiven themselves. As a man or woman thinks so he or she will speak. So turn to the cripple within your life and command – ‘Take up your bed and walk!’ Begin to live as the human that was created for greatness. You were never created to be an invalid. Healing is your portion and success is your right.

And for one final word from John Lennon, who was cut down in the prime of his life – “I’m not afraid of death because I don’t believe in it. It’s just getting out of one car, and into another.” 

 

How To Become A Great Finisher

The road to hell may or may not be paved with good intentions, but the road to failure surely is. Take a good look at the people you work with, and you’ll find lots of Good Starters — individuals who want to succeed, and have promising ideas for how to make that happen. They begin each new pursuit with enthusiasm, or at the very least, a commitment to getting the job done.

And then something happens. Somewhere along the way, they lose steam. They get bogged down with other projects. They start procrastinating and miss deadlines. Their projects take forever to finish, if they get finished at all.

Does all this sound familiar? Maybe a little too familiar? If you are guilty of being a Good Starter, but a lousy finisher — at work or in your personal life — you have a very common problem. After all, David Allen’s Getting Things Done wouldn’t be a huge bestseller if people could easily figure out how to get things done on their own.

More than anything else, becoming a Great Finisher is about staying motivated from a project’s beginning to its end. Recent research has uncovered the reason why that can be so difficult, and a simple and effective strategy you can use to keep motivation high.

In their studies, University of Chicago psychologists Minjung Koo and Ayelet Fishbach examined how people pursuing goals were affected by focusing on either how far they had already come (to-date thinking) or what was left to be accomplished (to-go thinking). People routinely use both kinds of thinking to motivate themselves. A marathon runner may choose to think about the miles already traveled or the ones that lie ahead. A dieter who wants to lose 30 pounds may try to fight temptation by reminding themselves of the 20 pounds already lost, or the 10 left to go.

Intuitively, both approaches have their appeal. But too much to-date thinking, focusing on what you’ve accomplished so far, will actually undermine your motivation to finish rather than sustain it.

Koo and Fishbach’s studies consistently show that when we are pursuing a goal and consider how far we’ve already come, we feel a premature sense of accomplishment and begin to slack off. For instance, in one study, college students studying for an exam in an important course were significantly more motivated to study after being told that they had 52% of the material left to cover, compared to being told that they had already completed 48%.

When we focus on progress made, we’re also more likely to try to achieve a sense of “balance” by making progress on other important goals. This is classic Good Starter behavior — lots of pots on the stove, but nothing is ever ready to eat.

If, instead, we focus on how far we have left to go (to-go thinking), motivation is not only sustained, it’s heightened. Fundamentally, this has to do with the way our brains are wired. To-go thinking helps us tune in to the presence of a discrepancy between where we are now and where we want to be. When the human brain detects a discrepancy, it reacts by throwing resources at it: attention, effort, deeper processing of information, and willpower.

In fact, it’s the discrepancy that signals that an action is needed — to-date thinking masks that signal. You might feel good about the ground you’ve covered, but you probably won’t cover much more.

Great Finishers force themselves to stay focused on the goal, and never congratulate themselves on a job half-done. Great managers create Great Finishers by reminding their employees to keep their eyes on the prize, and are careful to avoid giving effusive praise or rewards for hitting milestones “along the way.” Encouragement is important, but to keep your team motivated, save the accolades for a job well — and completely — done.

Nine Ways to use LinkedIn to Advance your Career

A new member joins LinkedIn every second. Since I first started writing about how to use LinkedIn as a job search tool, the professional social networking site has grown in reach and strength. According to spokeswoman Krista Canfield, LinkedIn now has more than 100 million users, with a new member joining every second. Its job postings have bulged to more than 62,000. When the company went public May 19, its shares surged above $100 before sliding below $70, but just today, a story in The New York Times reports that its lead underwriter, Morgan Stanley raised its price target to $88, saying LinkedIn could become a “standard utility for HR recruiters.” I’m now convinced that an active LinkedIn profile is essential for almost anyone who wants to cultivate a career. Even if you are satisfied in your job, LinkedIn can bring you unexpected opportunities. Canfield herself says she was sending a LinkedIn message to an old public relations client, asking for advice about travel to London and Paris, when the contact responded with the tip that LinkedIn was hiring. Canfield wound up getting the job. That’s the way traditional networking operates, but since it’s digital and nearly instantaneous, LinkedIn can be startlingly efficient.

1. Include more than your current job

If you are setting up your profile quickly and only want to include the bare bones, be sure to list as many of your past positions as possible. If you’ve been in your job only a few months, and that’s all you include, you will look like you are just starting your career. Canfield says that recruiters routinely search according to years of experience.

2. Add a photo
Canfield says LinkedIn has found that profiles with photos are seven times more likely to be viewed. Also, if you’re reaching out to old contacts, they may be more likely to remember your face than your name. If you’ve married and changed your name, a photo can clear up the confusion.

3. Connect to at least 50 people
LinkedIn has settled on 50 as the “magic number” that will increase your networking chances. Career coach Hellmann recommends 70 connections.

4. Connect with people you know.
Career coach Hellmann advises a do-unto-others rule when deciding whether to connect with other LinkedIn users. “If they’re total strangers, they’re not going to help you and you’re not going to help them,” he observes. Would you be willing to correspond with this person, and/or send an email on the contact’s behalf? Then you should connect. One caveat: Some people use LinkedIn to promote products, in which case they want a sprawling network, including strangers. But if you’re using LinkedIn as a job search tool, make sure you know your contacts well enough to want to network with them.

5. Personalize your communications
This is a pet peeve of mine. When you send a request to connect with someone, always take a moment to alter the default message, even if just to say something like, “Hey Jack, Let’s connect.” Think of how you feel when you receive a form letter. I feel alienated, and less inclined to respond.

6. Use the job postings
I frequently caution that job seekers should limit their time perusing online ads, but LinkedIn’s listings are worth reviewing. Click on a job and you will instantly see the contacts in your network who are connected to the company. In addition, coach Hellmann says he’s found that far fewer of them are false leads or listings by recruiters for positions that have already been filled. LinkedIn charges $295 for a 30-day posting.

7. Use the site’s “skills” link to help you find key words to include in your profile.
This is a new feature. Go to this link and brainstorm about your skills, typing them into the search box. On the left hand side of the page, you will get a list of related skills, each highlighted in blue. For those of us stumped about how to describe our talents in the form of crisp, web-search-friendly terms, this can help. Take the relevant phrases and words and plug them into the “Skills” section of your profile. Both Hellmann and Canfield say that hiring managers and recruiters frequently search for key words. Example: I plugged in “headline writing,” and I got “line editing and “news judgment,” both terms that hadn’t crossed my mind. The page also shows a bar graph that indicates how much a particular skill is growing. (Sadly, both headline writing and news judgment show only 1% hiring growth.) Hellmann also recommends scanning job ads in your field and noting the key words used.

8. For students: new jobs portal
Another new LinkedIn feature: a job portal designed for students and recent graduates. Companies do not pay to list these entry level jobs. Since it’s new, the listings are limited, but given how easy it is to use, it’s worth taking a look here for entry level jobs.

9. Try LinkedIn Today
LinkedIn is beefing up its editorial feature, which includes stories shared by contacts in your network. It now appears near the top of the “home” tab when you sign into LinkedIn. I’m agnostic about its utility, given all the other ways to search for industry news, but would say it’s worth a glance once a day.