Home > Articles > Data > MySQL

Data Types in MySQL

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

3.4 Working with Sequences

Many applications need to generate unique numbers for identification purposes. The requirement for unique values occurs in a number of contexts: membership numbers, sample or lot numbering, customer IDs, bug report or trouble ticket tags, and so forth.

MySQL’s mechanism for providing unique numbers is through the AUTO_INCREMENT column attribute, which enables you to generate sequential numbers automatically. However, AUTO_INCREMENT columns are handled somewhat differently by the various storage engines that MySQL supports, so it’s important to understand not only the general concepts underlying the AUTO_INCREMENT mechanism, but also the differences between storage engines. This section describes how AUTO_INCREMENT columns work in general and for specific storage engines so that you can use them effectively without running into the traps that sometimes surprise people. It also describes how you can generate a sequence without using an AUTO_INCREMENT column.

3.4.1 General AUTO_INCREMENT Properties

AUTO_INCREMENT columns must be defined according to the following conditions:

  • There can be only one column per table with the AUTO_INCREMENT attribute and it should have an integer data type. (AUTO_INCREMENT is also allowed for floating-point types, but is rarely used that way.)
  • The column must be indexed. It is most common to use a PRIMARY KEY or UNIQUE index, but it is allowable to use a non-unique index.
  • The column must have a NOT NULL constraint. MySQL makes the column NOT NULL even if you don’t explicitly declare it that way.

Once created, an AUTO_INCREMENT column behaves like this:

  • Inserting NULL into an AUTO_INCREMENT column causes MySQL to generate the next sequence number automatically and insert that value into the column. AUTO_INCREMENT sequences normally begin at 1 and increase monotonically, so successive rows inserted into a table get sequence values of 1, 2, 3, and so forth. Under some circumstances and depending on the storage engine, it may be possible to set or reset the next sequence number explicitly or to reuse values deleted from the top end of the sequence.
  • The value of the most recently generated sequence number can be obtained by calling the LAST_INSERT_ID() function. This enables you to reference the AUTO_INCREMENT value in subsequent statements even without knowing what the value is. LAST_INSERT_ID() returns 0 if no AUTO_INCREMENT value has been generated during the current connection.

    LAST_INSERT_ID() is tied only to AUTO_INCREMENT values generated during the current connection to the server. In particular, it is not affected by AUTO_INCREMENT activity associated with other clients. You can generate a sequence number, and then call LAST_INSERT_ID() to retrieve it later in the same connection, even if other clients have generated their own sequence values in the meantime.

    For a multiple-row INSERT that generates several AUTO_INCREMENT values, LAST_INSERT_ID() returns the first one.

    If you use INSERT DELAYED for storage engines that support delayed inserts, the AUTO_INCREMENT value is not generated until the row actually is inserted. In this case, LAST_INSERT_ID() cannot be relied on to return the sequence value.

  • Inserting a row without specifying an explicit value for the AUTO_INCREMENT column is the same as inserting NULL into the column. If ai_col is an AUTO_INCREMENT column, these statements are equivalent:

    INSERT INTO t (ai_col,name) VALUES(NULL,'abc');
    INSERT INTO t (name) VALUES('abc');
  • By default, inserting 0 into an AUTO_INCREMENT column has the same effect as inserting NULL. If you enable the NO_AUTO_VALUE_ON_ZERO SQL mode, inserting a 0 results in a 0 being stored, not the next sequence value.
  • If you insert a row and specify a non-NULL, non-zero value for an AUTO_INCREMENT column that has a unique index, one of two things will happen. If a row already exists with that value, a duplicate-key error occurs. If a row does not exist with that value, the row is inserted with the AUTO_INCREMENT column set to the given value. If this value is larger than the current next sequence number, the sequence is reset to continue with the next value after that for subsequent rows. In other words, you can “bump up” the counter by inserting a row with a sequence value greater than the current counter value.

    Bumping up the counter can result in gaps in the sequence, but you also can exploit this behavior to generate a sequence that begins at a value higher than 1. Suppose that you create a table with an AUTO_INCREMENT column, but you want the sequence to begin at 1000 rather than at 1. To achieve this, insert a “fake” row with a value of 999 in the AUTO_INCREMENT column. Rows inserted subsequently are assigned sequence numbers beginning with 1000, after which you can delete the fake row.

    Why might you want to begin a sequence with a value higher than 1? One reason is to make sequence numbers all have the same number of digits. If you’re generating customer ID numbers, and you expect never to have more than a million customers, you could begin the series at 1,000,000. You’ll be able to add well over a million customer records before the digit count for customer ID values changes.

  • For some storage engines, values deleted from the top of a sequence are reused. In this case, if you delete the row containing the largest value in an AUTO_INCREMENT column, that value is reused the next time you generate a new value. An implication of this property is that if you delete all the rows in the table, all values are reused and the sequence starts over beginning at 1.
  • If you use UPDATE to set an AUTO_INCREMENT column to a value that already exists in another row, a duplicate-key error occurs if the column has a unique index. If you update the column to a value larger than any existing column value, the sequence continues with the next number after that for subsequent rows. If you update the column by assigning 0 to it, it is set to 0 (regardless of whether NO_AUTO_VALUE_ON_ZERO is enabled).
  • If you use REPLACE to update a row based on the value of the AUTO_INCREMENT column, the AUTO_INCREMENT value does not change. If you use REPLACE to update a row based on the value of some other PRIMARY KEY or UNIQUE index, the AUTO_INCREMENT column is updated with a new sequence number if you set it to NULL, or if you set it to 0 and NO_AUTO_VALUE_ON_ZERO is not enabled.

3.4.2 Storage Engine-Specific AUTO_INCREMENT Properties

The general AUTO_INCREMENT characteristics just described form the basis for understanding sequence behavior specific to other storage engines. Most engines implement behavior that for the most part is similar to that just described, so keep the preceding discussion in mind as you read on.

3.4.2.1 AUTO_INCREMENT for MyISAM Tables

MyISAM tables offer the most flexibility for sequence handling. The MyISAM storage engine has the following AUTO_INCREMENT characteristics:

  • MyISAM sequences normally are monotonic. The values in an automatically generated series are strictly increasing and are not reused if you delete rows. If the maximum value is 143 and you delete the row containing that value, MySQL still generates the next value as 144. There are two exceptions to this behavior:
    • If you empty a table with TRUNCATE TABLE, the counter is reset to begin at 1.
    • Values deleted from the top of a sequence are reused if you use a composite index to generate multiple sequences within a table. (This technique is discussed shortly.)
  • MyISAM sequences begin at 1 by default, but it is possible to start the sequence at a higher value. With MyISAM tables, you can specify the initial value explicitly by using an AUTO_INCREMENT = n option in the CREATE TABLE statement. The following example creates a MyISAM table with an AUTO_INCREMENT column named seq that begins at 1,000,000:

    CREATE TABLE mytbl
    (
      seq INT UNSIGNED NOT NULL AUTO_INCREMENT,
      PRIMARY KEY (seq)
    ) ENGINE = MYISAM AUTO_INCREMENT = 1000000;

    A table can have only one AUTO_INCREMENT column, so there is never any ambiguity about the column to which the terminating AUTO_INCREMENT = n option applies, even if the table has multiple columns.

  • You can change the current sequence counter for an existing MyISAM table with ALTER TABLE. If the sequence currently stands at 1000, the following statement causes the next number generated to be 2000:

    ALTER TABLE mytbl AUTO_INCREMENT = 2000;

    If you want to reuse values that have been deleted from the top of the sequence, you can do that, too. The following statement will set the counter down as far as possible, causing the next number to be one larger than the current maximum sequence value:

    ALTER TABLE mytbl AUTO_INCREMENT = 1;

    You cannot use the AUTO_INCREMENT option to set the current counter lower than the current maximum value in the table. If an AUTO_INCREMENT column contains the values 1 and 10, using AUTO_INCREMENT = 5 sets the counter so that the next automatic value is 11.

The MyISAM storage engine supports the use of composite (multiple-column) indexes for creating multiple independent sequences within the same table. To use this feature, create a multiple-column PRIMARY KEY or UNIQUE index that includes an AUTO_INCREMENT column as its final column. For each distinct key in the leftmost column or columns of the index, the AUTO_INCREMENT column will generate a separate sequence of values. For example, you might use a table named bugs for tracking bug reports of several software projects, where the table is defined as follows:

CREATE TABLE bugs
(
  proj_name   VARCHAR(20) NOT NULL,
  bug_id      INT UNSIGNED NOT NULL AUTO_INCREMENT,
  description VARCHAR(100),
  PRIMARY KEY (proj_name, bug_id)
) ENGINE = MYISAM;

Here, the proj_name column identifies the project name and the description column contains the bug description. The bug_id column is an AUTO_INCREMENT column; by creating an index that ties it to the proj_name column, you can generate an independent series of sequence numbers for each project. Suppose that you enter the following rows into the table to register three bugs for SuperBrowser and two for SpamSquisher:

mysql> INSERT INTO bugs (proj_name,description)
    -> VALUES('SuperBrowser','crashes when displaying complex tables');
mysql> INSERT INTO bugs (proj_name,description)
    -> VALUES('SuperBrowser','image scaling does not work');
mysql> INSERT INTO bugs (proj_name,description)
    -> VALUES('SpamSquisher','fails to block known blacklisted domains');
mysql> INSERT INTO bugs (proj_name,description)
    -> VALUES('SpamSquisher','fails to respect whitelist addresses');
mysql> INSERT INTO bugs (proj_name,description)
    -> VALUES('SuperBrowser','background patterns not displayed');

The resulting table contents are as follows:

mysql> SELECT * FROM bugs ORDER BY proj_name, bug_id;
+--------------+--------+------------------------------------------+
| proj_name    | bug_id | description                              |
+--------------+--------+------------------------------------------+
| SpamSquisher |      1 | fails to block known blacklisted domains |
| SpamSquisher |      2 | fails to respect whitelist addresses     |
| SuperBrowser |      1 | crashes when displaying complex tables   |
| SuperBrowser |      2 | image scaling does not work              |
| SuperBrowser |      3 | background patterns not displayed        |
+--------------+--------+------------------------------------------+

The table numbers the bug_id values for each project separately, regardless of the order in which rows are entered for projects. You need not enter all rows for one project before you enter rows for another.

If you use a composite index to create multiple sequences, values deleted from the top of each individual sequence are reused. This differs from the usual MyISAM behavior of not reusing values.

3.4.2.2 AUTO_INCREMENT for MEMORY Tables

The MEMORY storage engine has the following AUTO_INCREMENT characteristics:

  • The initial sequence value can be set with an AUTO_INCREMENT = n table option in the CREATE TABLE statement, and can be modified after table creation time using that option with ALTER TABLE.
  • Values that are deleted from the top of the sequence normally are not reused. If you empty the table with TRUNCATE TABLE, the sequence is reset to begin at 1.
  • Composite indexes cannot be used to generate multiple independent sequences within a table.

3.4.2.3 AUTO_INCREMENT for InnoDB Tables

The InnoDB storage engine has the following AUTO_INCREMENT characteristics:

  • As of MySQL 5.0.3, the initial sequence value can be set with an AUTO_INCREMENT = n table option in the CREATE TABLE statement, and can be modified after table creation time using that option with ALTER TABLE.
  • Values that are deleted from the top of the sequence normally are not reused. If you empty the table with TRUNCATE TABLE, the sequence is reset to begin at 1. Reuse can occur under the following conditions as well. The first time that you generate a sequence value for an AUTO_INCREMENT column, InnoDB uses one greater than the current maximum value in the column (or 1 if the table is empty). InnoDB maintains this counter in memory for use in generating subsequent values; it is not stored in the table itself. This means that if you delete values from the top of the sequence and then restart the server, the deleted values are reused. Restarting the server also cancels the effect of using an AUTO_INCREMENT table option in a CREATE TABLE or ALTER TABLE statement.
  • Gaps in a sequence can occur if transactions that generate AUTO_INCREMENT values are rolled back.
  • Composite indexes cannot be used to generate multiple independent sequences within a table.

3.4.3 Issues to Consider with AUTO_INCREMENT Columns

You should keep the following points in mind to avoid being surprised when you use AUTO_INCREMENT columns:

  • Although it is common to use the term “AUTO_INCREMENT column,” AUTO_INCREMENT is not a data type; it’s a data type attribute. Furthermore, AUTO_INCREMENT is an attribute intended for use only with integer or floating-point types. Older versions of MySQL are lax in enforcing this constraint and will let you define a data type such as CHAR with the AUTO_INCREMENT attribute. However, only the integer or floating-point types work correctly as AUTO_INCREMENT columns.
  • The primary purpose of the AUTO_INCREMENT mechanism is to enable you to generate a sequence of positive integers. The use of non-positive numbers in an AUTO_INCREMENT column is unsupported. Consequently, you may as well define AUTO_INCREMENT columns to be UNSIGNED. With integer columns, using UNSIGNED also has the advantage of giving you twice as many sequence numbers before you hit the upper end of the data type’s range.
  • Don’t be fooled into thinking that adding AUTO_INCREMENT to a column definition is a magic way of getting an unlimited sequence of numbers. It’s not; AUTO_INCREMENT sequences are always bound by the range of the underlying data type. For example, if you use a TINYINT column, the maximum sequence number is 127. When you reach that limit, your application begins to fail with duplicate-key errors. If you use TINYINT UNSIGNED instead, the limit is extended to 255, but there is still a limit.
  • Clearing a table’s contents entirely with TRUNCATE TABLE may reset a sequence to begin again at 1, even for storage engines that normally do not reuse AUTO_INCREMENT values. The sequence reset occurs due to the way that MySQL attempts to optimize a complete table erasure operation: When possible, it tosses the data rows and indexes and re-creates the table from scratch rather than deleting rows one at a time. This causes sequence number information to be lost. If you want to delete all rows but preserve the sequence information, you can suppress this optimization by using DELETE with a WHERE clause that is always true, to force MySQL to evaluate the condition for each row and thus to delete every row individually:
    DELETE FROM tbl_name WHERE TRUE;

3.4.4 Tips for Working with AUTO_INCREMENT Columns

This section describes some useful techniques for working with AUTO_INCREMENT columns.

3.4.4.1 Adding a Sequence Number Column to a Table

Suppose that you create and populate a table:

mysql> CREATE TABLE t (c CHAR(10));
mysql> INSERT INTO t VALUES('a'),('b'),('c');
mysql> SELECT * FROM t;
+------+
| c    |
+------+
| a    |
| b    |
| c    |
+------+

Then you decide that you want to include a sequence number column in the table. To do this, issue an ALTER TABLE statement to add an AUTO_INCREMENT column, using the same kind of type definition that you’d use with CREATE TABLE:

mysql> ALTER TABLE t ADD i INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY;
mysql> SELECT * FROM t;
+------+---+
| c    | i |
+------+---+
| a    | 1 |
| b    | 2 |
| c    | 3 |
+------+---+

Note how MySQL assigns sequence values to the AUTO_INCREMENT column automatically. You need not do so yourself.

3.4.4.2 Resequencing an Existing Column

If a table already has an AUTO_INCREMENT column, but you want to renumber it to eliminate gaps in the sequence that may have resulted from row deletions, the easiest way to do it is to drop the column and then add it again. When MySQL adds the column, it assigns new sequence numbers automatically.

Suppose that a table t looks like this, where i is the AUTO_INCREMENT column:

mysql> CREATE TABLE t (c CHAR(10), i INT UNSIGNED AUTO_INCREMENT
    -> NOT NULL PRIMARY KEY);
mysql> INSERT INTO t (c)
    -> VALUES('a'),('b'),('c'),('d'),('e'),('f'),('g'),('h'),('i'),('j'),('k');
mysql> DELETE FROM t WHERE c IN('a','d','f','g','j');
mysql> SELECT * FROM t;
+------+----+
| c    | i  |
+------+----+
| b    |  2 |
| c    |  3 |
| e    |  5 |
| h    |  8 |
| i    |  9 |
| k    | 11 |
+------+----+

The following ALTER TABLE statement drops the column and then adds it again, renumbering the column in the process:

mysql> ALTER TABLE t
    -> DROP PRIMARY KEY,
    -> DROP i,
    -> ADD i INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    -> AUTO_INCREMENT = 1;
mysql> SELECT * FROM t;
+------+---+
| c    | i |
+------+---+
| b    | 1 |
| c    | 2 |
| e    | 3 |
| h    | 4 |
| i    | 5 |
| k    | 6 |
+------+---+

The AUTO_INCREMENT = 1 clause resets the sequence to begin again at 1. For a MyISAM, MEMORY, or InnoDB table, you can use a value other than 1 to begin the sequence at a different value. For other storage engines, omit the AUTO_INCREMENT clause, because they do not allow the initial value to be specified this way. The sequence will begin at 1.

Note that although it’s easy to resequence a column, and the question, “How do you do it?” is a common one, there is usually very little need to do so. MySQL doesn’t care whether a sequence has holes in it, nor do you gain any performance efficiencies by resequencing. In addition, if you have rows in another table that refer to the values in the AUTO_INCREMENT column, resequencing the column destroys the correspondence between tables.

3.4.5 Generating Sequences Without AUTO_INCREMENT

MySQL supports a method for generating sequence numbers that doesn’t use an AUTO_INCREMENT column at all. Instead, it uses an alternative form of the LAST_INSERT_ID() function that takes an argument. If you insert or update a column using LAST_INSERT_ID(expr), the next call to LAST_INSERT_ID() with no argument returns the value of expr. In other words, MySQL treats expr as though it was generated as an AUTO_INCREMENT value. This enables you to create a sequence number and then retrieve it later in your session, confident that the value will not have been affected by the activity of other clients.

One way to use this strategy is to create a single-row table containing a value that you update each time you want the next value in the sequence. For example, you can create and initialize the table like this:

CREATE TABLE seq_table (seq INT UNSIGNED NOT NULL);
INSERT INTO seq_table VALUES(0);

Those statements set up seq_table with a single row containing a seq value of 0. To use the table, generate the next sequence number and retrieve it like this:

UPDATE seq_table SET seq = LAST_INSERT_ID(seq+1);
SELECT LAST_INSERT_ID();

The UPDATE statement retrieves the current value of the seq column and increments it by 1 to produce the next value in the sequence. Generating the new value using LAST_INSERT_ID(seq+1) causes it to be treated like an AUTO_INCREMENT value, which allows it to be retrieved by calling LAST_INSERT_ID() without an argument. LAST_INSERT_ID() is client-specific, so you get the correct value even if other clients have generated other sequence numbers in the interval between the UPDATE and the SELECT.

Other uses for this method are to generate sequence values that increment by a value other than 1, or that are negative. For example, this statement can be executed repeatedly to generate a sequence of numbers that increase by 100 each time:

UPDATE seq_table SET seq = LAST_INSERT_ID(seq+100);

Repeating the following statement generates a sequence of decreasing numbers:

UPDATE seq_table SET seq = LAST_INSERT_ID(seq-1);

You can also use this technique to generate a sequence that begins at an arbitrary value, by setting the seq column to an appropriate initial value.

The preceding discussion describes how to set up a counter using a table with a single row. That’s okay for a single counter. If you want several counters, add another column to the table to serve as a counter identifier, and use a different row in the table for each counter. Suppose that you have a Web site and you want to put some “this page has been accessed n times” counters in several pages. Create a table with two columns. One column holds a name that uniquely identifies each counter. The other holds the current counter value. You can still use the LAST_INSERT_ID() function, but you determine which row it applies to by using the counter name. For example, you can create such a table with the following statement:

CREATE TABLE counter
(
  name  VARCHAR(255) CHARACTER SET latin1 COLLATE latin1_general_cs NOT NULL,
  value INT UNSIGNED,
  PRIMARY KEY (name)
);

The name column is a string so that you can name a counter whatever you want, and it’s defined as a PRIMARY KEY to prevent duplicate names. This assumes that applications using the table agree on the names they’ll be using. For Web counters, uniqueness of counter names is ensured simply by using the pathname of each page within the document tree as its counter name. The name column has a case-sensitive collation to cause pathname values to be treated as case sensitive. (If your system has pathnames that are not case sensitive, use a collation that is not case sensitive.)

To use the counter table, the INSERT ... ON DUPLICATE KEY UPDATE statement is useful, because it can insert a new row for a page that has not yet been counted, or update the count for an existing page. Also, by using LAST_INSERT_ID(expr) to generate the counter value, you can easily retrieve the current counter after updating it. For example, to initialize or increment the counter for the site’s home page, and then retrieve the counter for display, do this:

INSERT INTO counter (name, value)
  VALUES('index.html', LAST_INSERT_ID(1))
  ON DUPLICATE KEY UPDATE value = LAST_INSERT_ID(value+1);
SELECT LAST_INSERT_ID();

An alternative approach for incrementing counters of existing pages without using LAST_INSERT_ID() is to do this:

UPDATE counter SET value = value+1 WHERE name = 'index.html';
SELECT value FROM counter WHERE name = 'index.html';

However, that doesn’t work correctly if another client increments the counter after you issue the UPDATE and before you issue the SELECT. You could solve that problem by putting LOCK TABLES and UNLOCK TABLES around the two statements. Or you could create the table using a transactional storage engine and update the table within a transaction. Either method blocks other clients while you’re using the counter, but the LAST_INSERT_ID() method accomplishes the same thing more easily. Because its value is client-specific, you always get the value you inserted, not the one from some other client, and you don’t have to complicate the code with locks or transactions to keep other clients out.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020