A way to get a large number of steam keys. Natural keys versus artificial keys. Typical arguments for EC supporters

Michael will give you a gun at every conversation with him, but here he appears every time in different places.
For the first time, he will most likely be standing next to Dr. Zed. He has glasses on his face and a cannon behind his back.
Here is a map of the places of all his appearances:

Also located in the Sanctuary. The developers made a separate statement about them: it contains extremely valuable loot, but here's the annoyance, they give the key to the players only 1. Also, the developers forced to buy Season Pass to give another one. Thus, we are forced to carefully plan the opening of the chest and endure to the last, because it is much more logical to open it at high levels, so that the contents are extremely valuable.

About the nature of the problem

Each entry in the table included in the RDBMS must have a primary key (PC) - a set of attributes that uniquely identifies it in the table. The case when the table does not have a primary key has a right to exist, however, this article is not considered.

As a primary key can be used -
Natural Key (EC) - a set of attributes described by a record of an entity that uniquely identifies it (for example, a passport number for a person);
or
Surrogate Key (SC) - an automatically generated field that is not connected in any way with the information content of the record. Usually, an auto-increment field of the INTEGER type acts as a SC.

There are two opinions:

1. SCs should be used only if the EC does not exist. If the EC exists, then the identification of the record inside the database is carried out according to the existing EC;
2. ICs must be added to any table to which references exist (REFERENCES) from other tables, and relations between them should be organized only with the help of ICs. Of course, the search for the record and its presentation to the user are still carried out on the basis of the EC.

Naturally, you can imagine some kind of intermediate opinion, but now the discussion is conducted in the framework of the two above.

When do SK appear

To understand the place and importance of SC, we consider the design stage at which they are introduced into the database structure and the methodology for their introduction.

For clarity, we consider a database of 2 relationships - Cities (City) and People (People). We assume that the city is characterized by a Name, all cities have different names, a person is characterized by a Family name, Passport number and city of residence (City). We also believe that each person has a unique passport number. At the stage of compiling the infological model of the database, its structure is the same for both the EC and the IC.

CREATE TABLE City (Name VARCHAR (30) NOT NULL PRIMARY KEY); CREATE TABLE People (Passport CHAR (9) NOT NULL PRIMARY KEY, Family VARCHAR (20) NOT NULL, City VARCHAR (30) NOT NULL REFERENCES City (Name));

Everything is ready for the EC. For SK, we do one more step and transform the tables as follows:

CREATE TABLE City (/ * In various dialects sQL language the auto-increment field will be expressed differently - for example, through IDENTITY, SEQUENCE or GENERATOR. Here we use the AUTOINCREMENT symbol. * / Id INT NOT NULL AUTOINCREMENT PRIMARY KEY Name VARCHAR (30) NOT NULL UNIQUE); CREATE TABLE People (Id INT NOT NULL AUTOINCREMENT PRIMARY KEY, Passport CHAR (9) NOT NULL UNIQUE, Family VARCHAR (20) NOT NULL, CityId INT NOT NULL REFERENCES City (Id));

Please note that:

• All conditions dictated by the subject area (uniqueness of the city name and passport number) continue to be present in the database, only provided not by the PRIMARY KEY condition, but by the UNIQUE condition;
• The AUTOINCREMENT keyword is not found in any of the servers I know. This is just a designation that the field is generated automatically.

In general, the algorithm for adding SK is as follows:

1. The INTEGER AUTOINCREMENT field is added to the table;
2. It is declared PRIMARY KEY;
3. Old PRIMARY KEY (ЕК) is replaced by UNIQUE CONSTRAINT;
4. If the table has REFERENCES for other tables, then the fields included in the REFERENCES are replaced with one field of type INTEGER, which makes up the primary key (as People.City is replaced by People.CityId).

This is a mechanical operation that does not violate the infological model and data integrity. From the point of view of the infological model, these two databases are equivalent.

Why is all this necessary?

A reasonable question arises - why? Indeed, enter some fields into the tables, replace something, why? So, what do we get by doing this “mechanical” operation.

Simplification of maintenance

This is an area where SCs have the greatest benefits. Since the communication operations between the tables are separated from the logic “inside the tables”, both can be changed independently and without affecting the rest.

For example, it turned out that cities have duplicate names. It was decided to introduce another field in City - Region (Region) and make a PC (City, Region). In the case of the EC - the City table is changed, the People table is changed - the Region field is added (yes, yes, I am silent about all sizes), all requests are rewritten, including on clients in which City participates, and the line AND XXX is added to them .Region \u003d City.Region.

Yes, I almost forgot, most servers strongly dislike ALTER TABLE on the fields included in the PRIMARY KEY and FOREIGN KEY.

In the case of SK - a field is added to City, UNIQUE CONSTRAINT is changed. All.

Another example - in the case of SK, changing the list of fields in SELECT never forces you to rewrite JOIN. In the case of the EC - a field was added that is not included in the PC of the linked table - rewrite.

Another example - the data type of the field included in the EC has changed. And again alterations of a heap of tables, again optimization of indexes ...

In the context of changing legislation, this advantage of the UK alone is sufficient for their use.

DB size reduction

Assume in our example that the average length of a city name is 10 bytes. Then for each person on average there will be 10 bytes for storing a link to the city (actually, a little more due to official information on VARCHAR and much more due to the People.City index, which will have to be built in order for REFERENCES to work efficiently). In the case of SC, 4 bytes. Savings - a minimum of 6 bytes per person, approximately 10 MB for the city of Novosibirsk. Obviously, in most cases, reducing the size of the database is not an end in itself, but this, obviously, will lead to an increase in speed.

Arguments were made that the database itself could optimize the storage of the EC by substituting a certain hash function instead of it in People (actually creating the IC itself). But none of the really existing commercial database servers does this, and there is reason to believe that it will not. The simplest justification for this opinion is that with such a substitution, the banal ADD CONSTRAINT ... FOREIGN KEY or DROP CONSTRAINT ... FOREIGN KEY operators will lead to a serious shaking of tables, with a noticeable change in the entire database (it will be necessary to physically add or delete (with replacement by a hash function )) all fields included in CONSTRAINT.

Faster data sampling

The question is quite controversial, however, based on the assumption that:

• The database is normalized;
• There are many entries in the tables (tens of thousands or more);
• Queries primarily return limited data sets (maximum units of percent of table size).

system performance on the SC will be significantly higher. And that's why:

ECs can potentially give higher performance when:

• Only information that is part of the primary keys of related tables is required;
• there are no WHERE clauses on fields in related tables.

That is, in our example, this is a request of the type:

SELECT Family, City FROM People;

In the case of SK, this request will look like

SELECT P. Family, C. Name FROM People P INNER JOIN City C ON P. CityId \u003d C.Id;

It would seem that the EC gives a simpler query with fewer tables, which will execute faster. But here it’s not so simple: the size of tables for the EC is larger (see above) and disk activity will easily eat up the advantage gained due to the lack of JOIN. This will be even more pronounced if filtering is used when sampling data (and if it is of any significant amount of tables, it is used necessarily). The fact is that the search is usually carried out by informative fields such as CHAR, DATETIME, etc. Therefore, it is often faster to find a set of values \u200b\u200bin the lookup table that limits the result returned by the query, and then select the appropriate records from the large table by JOIN using a fast INTEGER index. For example:

will run many times slower than

In the case of the EC, there will be an INDEX SCAN of the large People table by the CHARACTER index. In the case of SK - INDEX SCAN less CITY and JOIN effective INTEGER index.

But if we replace \u003d ‘Ivanovo’ with LIKE ‘% vanovo’, then we will talk about braking the EC relative to the SC by an order of magnitude or more.

Similarly, as soon as in the case of the EC, it will be necessary to include in the request a field from City that is not included in its primary key, the JOIN will be carried out at a slow index and the performance will drop significantly below the SK level. Everyone can draw conclusions himself, but let him remember what percentage of the total number of his queries is SELECT * FROM The only table. At me - negligible.

Yes, supporters of the EC love to carry out as an advantage the “informativeness of tables”, which is growing in the case of the EC. Once again I repeat that the table containing the entire database in the form of a flat-file has the maximum information content. Any “increase in the information content of tables” is an increase in the degree of duplication of information in them, which is not good.

Increase data refresh rate

At first glance, the EC is faster - no need to generate an extra field with INSERT and check its uniqueness. In general, the way it is, although this slowdown manifests itself only at a very high transaction intensity. However, this is not obvious, because some servers optimize record insertion if a monotonically increasing CLUSTERED index is built on the key field. In the case of SC, this is elementary; in the case of EC, alas, it is usually unattainable. In addition, INSERT will go faster to the table on the MANY side (which happens more often), because REFERENCES will be checked at a faster index.

When updating the field included in the EC, you will have to cascade the update of all related tables. So, renaming Leningrad to St. Petersburg will require a transaction with several million records with our example. Updating any attribute in the system with SK will result in updating only one record. Obviously, in the case of a distributed system, the availability of archives, etc. the situation will only get worse. If the fields are not included in the EC, the performance will be almost the same.

More about CASCADE UPDATE

Not all database servers support them at the declarative level. The arguments "this is your curve server" in this case are hardly correct. This forces you to write separate logic for the update, which is not always easy (cited good example - in the absence of CASCADE UPDATE, it is impossible to update the referenced field at all - you must disable REFERENCES or create a copy of the record, which is not always valid (other fields may be UNIQUE)).

In the case of SK, it will be executed faster, for the simple reason that the REFERENCES check will go at a fast index.

Are there any good ECs?

Nothing lasts forever under the moon. The seemingly most reliable attribute is suddenly canceled and ceases to be unique (I won’t go far - the ruble is ordinary and the ruble is denominated, for example there are no numbers). Americans swear at the unnaturalness of the social security number, Microsoft at the Chinese gray network cards with duplicate MAC addresses, which can lead to duplication of GUIDs, doctors perform sex reassignment operations, and biologists clone animals. Under these conditions (and taking into account the law of non-decreasing entropy), lay the thesis on the invariance of the EC in the system - lay a mine for yourself. They must be allocated in a separate logical layer and, if possible, isolated from other information. So their change is experienced much easier. And indeed: to unambiguously associate an entity with some of the attributes of this entity - well, it’s strange, perhaps. The passport number is not yet a person. SK, on \u200b\u200bthe other hand, is a certain substance, meaning the essence. It is the essence, and not some of its attributes.

Typical arguments for EC supporters

In the system with SK, the correctness of information input is not controlled

This is not true. Control would not be carried out if the uniqueness restriction were not imposed on the fields included in the EC. Obviously, if the subject area dictates some restrictions on the attributes of the EC, then they will be reflected in the database in any case.

There are fewer JOINs in a system with an EC, therefore, requests are simpler and development is more convenient

Yes, less. But, in a system with SC, it is trivially written:

CREATE VIEW PeopleEK AS SELECT P.Family, P. Passport, C. Name FROM People P INNER JOIN City C ON P. CityId \u003d C.Id

And you can have all the same charms. With more, however, high speed. It’s good to mention that in the case of the EC, many will have to program cascade operations, and, God forbid, in a distributed environment, deal with performance issues. Against this background, “short” requests no longer seem so attractive.

The introduction of SC violates the third normal form

Recall the definition: A table is in the third normal form (3NF) if it satisfies the definition of 2NF, and none of its non-key fields depends functionally on any other non-key field.

That is, there is no talk of key fields there at all. Therefore, adding another key to the table can in no way violate 3NF. Generally, for a table with several possible keys it makes sense to talk not about 3 NF, but about the Normal Boyce-Codd Form, which is specially introduced for such tables.

What is a key? Its importance for programs and games

The key is a combination of numbers and letters to activate a program or game.
The concept of a key is now very relevant in the Internet environment, since most programs and games are activated by entering a specific key.
Each program and game has its own unique code and, as a rule, it is designed for only one computer. Of course, there are exceptions (/ / etc.) in these programs, one key can act on several (thousand) computers, tablets, laptops. Of course, this is not the whole range of programs for which it works. But as a rule, one code works for several programs. If you take games, in the same way, then one license code is equal to one activated game and nothing else.

Why the key?

1. Worked in all its glory, that is, without any bugs and as expected. As a rule, keys greatly improve performance, even with a hacked program.
2. If you have a key, then you can use free, technical support. Sometimes these actions are even better than looking for an answer on the Internet “why isn't the antivirus updated”
3. Show off to your friends that you have a license. These actions are usually relevant when using licensed games that can be activated in Steam or other similar services for the sale and download of licensed games.
4. You will always have current updates for the program. For the same antiviruses - this is a very necessary measure.

Where to get the key?

There are 3 ways to get the keys:

1 - Buy. This can be done with the creators of the program or game, or with intermediaries. For example, you can purchase some keys in our online store, or rather in the store section

2 - Get a Trial (temporary) key for a limited period (usually up to 3 months). These opportunities are usually given antivirus software at the first installation or similar keys can be found in thematic groups for certain types. For example, we have a group for Kaspersky keys

Like most licensed software, operating windows system 10 is a paid product. But she also has a “shareware” version. Each user decides whether to leave a trial version on the computer or still go through the process of OS activation. Those who opted for the licensed version can get the coveted activation key in several ways.

Why activate Windows 10

The "shareware" (non-activated) version of Windows 10 almost does not limit functionality OS Outwardly, it differs from the activated version only in that at the bottom of the desktop, above the taskbar, a “watermark” hangs all the time - a reminder of windows activation. In addition, the user of the inactive version is deprived of the opportunity to personalize the system, that is, change the desktop wallpaper, icons, loading screens, color themes, and so on. There is nothing critical to work in this, but still, these seemingly insignificant restrictions may sooner or later become annoying. In this case, it makes sense to activate Windows using one of the methods described below.

How to activate Windows 10 without a license key

So, you decided to activate your windows version 10. If you have an activation key, then there is nothing complicated about it. But what if there is no key? In this case, there are also ways to legally activate the OS. Microsoft offers a choice of two proven and safe methods:

• digital Entitlement Method
• windows 10 activation by phone.

Digital Entitlement Method

In the Russian translation, the activation method of Digital Entitlement is called "Digital Resolution". Initially, it was intended only for users participating in the Windows Insider program, created by Microsoft for preliminary testing and evaluation of Windows. Then, “digital resolution” became available to everyone during the campaign free update from versions 7 and 8.1 to Windows 10.

You can obtain a “digital license” on a PC by linking a Microsoft account to the installed OS through the “Activation” setting in the “Update and Security” settings, after which you will no longer need to activate Windows 10. But you still need to enter it on your own at least once PC license key Windows.

To get in the number windows users Insider and get the coveted "digital resolution", you must:

1. Go to the "Start - Control Panel - Update and Security" menu. Go to the "Windows Insider Program" section and click the "Start" button.
   You can also open the settings window by finding the required parameter through the Windows search window
2. In the window that appears, you must log in to your Microsoft account (if it is not there, then you will be asked to create it).
   You can also create a Microsoft account on the official website of the corporation.
3. Then the user will be offered a choice of one of three packages of Windows Insider assemblies, which differ in the "dampness" of system components. These packages, respectively, allow you to:
   
4. After choosing a package windows builds Insider needs to restart the PC.
   You can restart your PC later
5. At the next boot of the system, you need to enter the “Update and Security” setting, then open the “Center” window windows updates"And click the" Check for Updates "button to download the necessary windows package Insider.
   Sometimes loading the necessary assembly of Windows Insider is done automatically immediately after rebooting the PC
6. Done, now you own the “digital resolution” of Windows.

Video: How to Join Windows Insider

The author of this article would like to warn users who are going to resort to such a method of obtaining "digital resolution". Firstly, the downloaded version of Windows 10 will be test and will not be able to guarantee the stable operation of all components. Secondly, you very often have to update the OS, as the number of test cases coming out windows components large enough. And thirdly, this type of system activation does not actually provide the user with an official licensed version of Windows, but a trial version that lasts 90 days, followed by auto renew for a similar period. Sometimes about the fact of use trial version can warn a "watermark" appearing on the desktop.

Activating Windows 10 by Phone

This is another official Microsoft Windows 10 activation method. You need to do the following:

1. Press WIN + R to invoke the command windows string, type slui 4 and press Enter.
   Run command line Windows can also be clicked. right click mouse on the Start icon and selecting the appropriate menu
2. In the window that appears, the “Windows Activation Wizard”, after choosing the region of residence, an information window opens with the phone number you want to call and the installation code.
   Click on the "Enter confirmation code" button only after the answering machine confirms the correctness of the setup code you entered
3. Call provided toll free numberfollow further step by step instructions answering machine. At the end, you will be asked to enter the installation code on the phone.
4. After entering the installation code, the answering machine will dictate a Windows activation confirmation code to you. It will need to be entered in the confirmation window.
   
   If the confirmation code is entered correctly, then after clicking the "Activate Windows" button, a window appears confirming the end of the activation process
5. After entering the appropriate code, hang up, press the “Activate Windows” button, and then “Finish”.
   After the process of activation of Windows 10 by phone is completed, the corresponding entry will appear in the settings of the "Activation" parameter
6. Reboot the PC. Your version of Windows 10 is now activated.

Video: Activating Windows 10 by Phone

Windows 10 Phone Activation Security Level

This method of activating Windows 10 is one of the safest, as the whole process is carried out privately, without the participation of any third parties (activation is performed by an automated answering machine). In addition, you do not transmit any personal data or information that threatens the security of your PC and operating system. It’s worth remembering only one rule: call only the numbers specified in the “Windows Activation Wizard by Phone”.

Problems Activating Windows 10 by Phone

Sometimes the activation method over the phone may not work. The most common problems that occur are:

1. "Data not recognized." Either the Windows activation confirmation key was entered incorrectly - check and enter it again. Either the key is not suitable for installed version Windows - then you need to contact Microsoft Technical Support).
2. "Reset call". The reason may be failures on the line or the technical work of the Microsoft call-center. It is best to call on weekdays from 9:00 to 20:00 Moscow time.
3. "Sync Error." Occurs when time settings fail and windows dates. If the time and date are set correctly, try synchronizing using the Internet via bottom panel Management "Date and time".

Deferred activation of Windows 10

As you know, an inactive version of Windows 10 is available for use only within 30 calendar days.. After this period the system simply stops loading, giving out only a window with a message about the need to activate the OS. However, in fact, Windows 10 can work without activation for as long as 90 days. To do this, use the Microsoft Delay Activation feature.

The following is required:

Video: How to extend the trial period for Windows 10 through the command line console

Activating Windows 10 after replacing PC accessories

If you have a licensed version of Windows 10 installed and you decide to replace components on your computer, this may lead to a reset of the OS activation key. However, it will not be possible to reuse a valid license. Most often this problem occurs when replacing motherboard . To reactivate the OS, do the following:

1. IN windows settings go to the Update and Security console and open the Activation window. Select the Troubleshooting menu.
   When a hardware component is changed, an entry appears in the activation section warning that your version of the OS is not activated
2. The activation system will display a message like: "Windows could not be activated on this device." Click on the line "The hardware components have recently been changed on this device."
   You will also be asked to go to windows store to purchase new version OS
3. You will then be asked to log in through your Microsoft personal account.
   If you are already logged in, this step will be automatically skipped.
4. A window will appear with a choice of the hardware component that has been replaced on your PC. Having checked the corresponding item, click the "Activate" button.
   If you changed several hardware components at once, then in the presented list you must select all of them
5. Done. Your version of Windows 10 is reactivated.
   After troubleshooting the settings, a record appears about the successful completion of Windows 10 activation

How to purchase a Windows 10 license key

There are several ways to purchase a license key to activate Windows 10. Consider the most popular of them.

Microsoft Digital Store

It is the fastest and safe way . After completing the purchase, you will receive a digital key to activate your version of Windows 10. To purchase:

1. Go to the official Microsoft website. IN windows section click on the "Buy Windows 10" button.
   
   To quickly navigate the site, you can use the search bar
2. You will be offered to choose two OS versions: “Home” and PRO (“Professional”). The difference between them is that in pRO version There is an expanded functionality and an improved data protection system. Click on the button "Buy Windows 10".
   
   By clicking on the “Buy” button, you will be redirected to the page with detailed description functions and capabilities of each OS version
3. On the next page, where the benefits of the new OS will be described in detail, you must click on the "Add to Cart" button, and then on the "Checkout".
   Only credit / debit card is available from payment methods
4. Done. License key will be sent to your mail, which is used in your Microsoft account. This key will need to be entered in the "Activation" settings of the "Update and Security" console.

Other ways to purchase a key

There are other, quite convenient, but varying in price and degree of reliability methods of acquiring a Windows 10 activation key.

A reliable, but less expensive way to purchase a licensed version of the OS.When using it, the benefit can be about 1-2 thousand rubles. You can’t buy a boxed version on the official Microsoft website, you need to buy it in digital stores.

The kit includes:

• bootable USB device with Windows 10;
• digital activation code;
• paper system installation instructions.

Buying equipment with Windows 10 installed

The most expensive way to purchase an OS.In this case, Windows 10 will, in fact, only complement the hardware. Most often, this method is resorted to by users who decide to completely upgrade the hardware of the PC. In this case, the system unit pre-assembled in the store with installed windows 10 will be cheaper than buying sets and OS separately.

Purchase through third-party trading platforms

The least expensive way to acquire a Windows license, but the most unreliable. You can buy a Windows 10 digital key on any well-known trading platform, for example, on eBay.com. The risks associated with such a purchase are different. They may sell you a non-working key or its “OEM version” (a key that is already tied to specific equipment). The seller can make a substitution of the OS version (for example, instead of 64-bit sell 32-bit). Deven if the site (like, say, on eBay) has a refund function within 30 days, this still does not guarantee the security of the transaction.

The author of this article has often heard negative reviews from users purchasing third-party license keys for Windows trading floors. Sometimes the keys were simply inoperative. Sometimes, after a certain period of time, such keys are “revoked” (became unusable) due to the fact that the purchased digital license was an “OEM version”. Therefore, the author advises: if you decide to buy a key, for example, on eBay, then carefully read the description, check with the seller for information about the type and version of the key, and also check the availability of the money back function.

There are many legal ways to activate Windows 10 in order not to resort to illegal methods. Any user can register in windows program Insider from Microsoft, having received the appropriate digital license, or activate the OS by phone. In addition, there is always the opportunity to buy both a digital and physical (boxed) version of Windows 10 or purchase it in a kit with an already assembled system unit. And if you need to save as much as possible, then you can buy a key on third-party trading floors, however, only at your own peril and risk.

On Steam, there are two ways to get the game for free from another player or company. This is a gift and cd-key. This article will look at how they differ and how to get a Steam CD-Key for free.

What is the difference between a gift and a Steam key

First, let's figure out what is the difference between Steam CD-Key and gift (Gift, gift). Both allow you to get a full game, but in the case of a gift there is one significant difference. By receiving a CD-Key you can only activate the game for yourself. Immediately after entering the key, it will be added to your library. Of course you can give the key to a friend, for example by sending e-mail, but only if you haven’t activated it in your account.

In the case of a gift, you get a link by clicking on which you enter your username and password and you have the opportunity to activate the game or put in inventory. In the second case, from the inventory you can activate it later or transfer it to a friend through Steam. You cannot transfer a game that you have already activated.

How to activate Steam CD-Key

When did you receive the key steam games then start the client and go to the game library. Next, click on the add game button below, then select "Activate on Steam."

Then, in the window that opens, click the next button, accept the agreement and finally enter the game key. You must enter exactly as you received it - symbol to symbol!

After entering, check the key again and click the "Next" button. Congratulations! The game is activated!

How to get free Steam keys

Until recently, I told you about the method, but in this article we will talk about something else. Ways to get free key huge variety! The key can be obtained by participating in competitions of various gaming sites, or VKontakte or facebook groups. But I will talk about one site where this business is essentially put on stream. The site is called GAMEKIT. The creators of the site are partners of many games and have organized a certain community. After registering on the site, you need to perform simple tasks for which you will receive points.

For points in the future you can get many different rewards for example:

• PremiumSteam CD-key for free;
• Steam gift card for 5 or 10 EUR;
• 10 random Steam keys;
• Weapon for the game