Difference Between ALTER and UPDATE (in IT terms)

Edited by Diffzy | Updated on: April 30, 2023


Difference Between ALTER and UPDATE (in IT terms)

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While ordinarily, the word 'alter' in English means to 'change' something, the word 'update' means to 'check the status of something'. On the other hand, in IT, both these SQL commands have seemingly different functions. However, both these functions are true to their names. Knowing the English Dictionary's meanings helps us understand the meanings of both words that otherwise seem like mainly IT-focused language.

Did you know that both terms are ALSO considered commands or queries in SQL? So, what is SQL? SQL, when expanded, is also known as Structured Query Language. SQL is a programming language that is used by many companies and organizations that store large amounts of relational data as part of their daily grind. 

Many people may not know what SQL is. To an average Joe, who knows nothing about SQL, the concept of ALTER AND UPDATE may sound UNHEARD-OF. For the record, SQL is said to be a very commonly used database language that is used in many organizations and corporates that employ billions of people around the world.

Such companies generally are known to store large amounts of data related to stocks, products, people, or even their orders! This is why a little knowledge of SQL can prove helpful! That is why you should consider reading the rest of this article!

The terms ALTER and UPDATE, when used in IT, are also called SQL commands. These two SQL commands (also called queries) are used to change the 'attributes' of relations (tables) in databases and/or to update existing records in databases.

Ever wonder that perhaps SQL commands were given these names because they help with similar SQL functions (with regard to Databases)? Does it help to know their English language meanings? It sure does! Observe how both words mean almost the same thing as their It-related function. It also helps to remember their meanings when you know this for a fact. The English word UPDATE, in its basic verb form, means to 'make something more modern or up-to-date' or 'simply the act of updating'. Just knowing its definition in the English Dictionary can help you remember the meaning of the SQL command UPDATE as well! The meaning of the UPDATE command in relation to Databases seems to do the same MAGIC with updating, editing, or modifying existing tables in a database. We will learn more about it in the rest of the article. The meaning of UPDATE indeed is similar, both as a verb in the Dictionary, and with respect to SQL.

Knowing this is a repose that makes it somewhat more digestible for a novice who knows nothing about IT. Consider the sentence 'I have to update my address book'. Similarly, the English word 'alter' is used in a similar way. We know it is normally used to describe a 'change in character or composition typically in a comparatively small but significant way'.The SQL command ALTER works with a table's columns or attributes, specifically to add, delete or modify them.

Consider its use in a sentence: 'You'll have to alter this dress before the ceremony'. Thus it is really a helpful thing that the person who coined these terms in SQL programming really did a good thing when he/she kept similar names.

It is indeed helpful to know that both these SQL query names have the same meanings as their related functions. Let us go deeper then and discover the meanings of both SQL terms, i.e., UPDATE and ALTER, in the IT world. Let's find out if they WERE indeed named with the same idea in mind.


The ALTER command (SQL) is considered to be something known as a DDL command. There's another fancy word. When expanded, DDL means Data Definition Language. Remember also that the UPDATE command is considered to be a DML command. Yet another fancy term. DML, on the other hand, when expanded, means Data Manipulation Language.

Both these SQL commands are used to either add or modify Data in Databases. Both commands are said to alter data effectively as well. In this section, we will try to stick to purely SQL (IT-related) explanations just so that we can get our basic SQL concepts right. (There is no English Dictionary stuff here, by the way, and we will get back to that at the end of the article)

 The basic syntax of both SQL commands UPDATE and ALTER is very different too. Observe both very apt SQL commands. Take note of how they can be used to manipulate and control Data in relation to tables (IT-related talk)

Consider the syntax of the ALTER command, which of course, only an IT technician would tell you:

ALTER TABLE table_name ADD column_name datatype;

The syntax of the UPDATE command:

UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition;

Has reading the above got you thinking? Has it gotten you curious? Consider examining the following table given below for the actual differences between both terms. This time it is presented in a tabular format.

Difference Between Alter and Update in Tabular Form

Parameters of Comparison ALTER UPDATE
Connotation ALTER is an SQL command that is often used to edit an RDBMS‘s datasets, tables etc. UPDATE is just an SQL command which is used to change the rows inside an RDBMS’s table. Hence this is the main difference between ALTER and UPDATE commands.
Type of Command ALTER is a Data Definition Language (DDL) command. UPDATE is a Data Manipulation Language (DML) command.
Usability ALTER command is known to modify the schema of the database. The UPDATE command is known to modify the content in a data structure. This is yet another difference between ALTER and UPDATE
Purpose ALTER command is used to add, modify or erase values of database relations. UPDATE is used to change existing information in the database.
Sets Values as ALTER command sets all tuple entries to NULL. UPDATE command gives the values indicated in the query to the tuples.

What is ALTER?

Again, let us analyze the meaning of each SQL command separately. To be more specific, the ALTER command is used for altering the table structure. It is used to add, modify or delete columns in a table. There are many forms of the ALTER command that are used, for example, 'ADD', 'DROP', and 'MODIFY'.

The ALTER command is also called a DDL function (DDL, when expanded, means Data Definition Language, as mentioned earlier). This query may be used to change a relationship in a table. This can be done by adding deleting, and dropping columns.

The ALTER query also allows us to rename and resize columns or change the file format of columns in an existing table (relation) inside the databases.

What is UPDATE?

On the other hand, the UPDATE command in SQL is used to update existing rows (records) in a table. If you didn't know, there are three kinds of update commands in SQL. What are they? They are INSERT, UPDATE and DELETE.

Difference Between ALTER and UPDATE in Points

  • The first difference is that UPDATE query is a Data Manipulation Language (DML) command. On the other hand, ALTER is a Data Definition Language (DDL)
  • The second difference is that ALTER Query is known to add, modify, delete, and rename relations in a table;On the other hand the UPDATE command is known to simply update or adjust entries in the table.
  • The ALTER query in SQL is known to set the entries of all records to NULL. On the other hand, The UPDATE query gives the value indicated within the query to the relation's tuples from the other end.
  • The ALTER query is used exclusively for attributes or columns, whereas the UPDATE query is used mainly for feature values.
  • The ALTER query updates the database layout and conformity in SQL. On the other hand, The UPDATE query changes the values of a data structure.


Now that we have analyzed the meaning of ALTER and UPDATE in IT terms, we can get back to the erstwhile discussion. From the above, it is indeed obvious that the two SQL commands, namely UPDATE and ALTER have entirely different functions. They are both called commands that are used in SQL.

The ALTER command is normally used to add, modify or delete columns in an existing table. On the other hand, the UPDATE command is used to modify existing rows in a table (relational aspect) by inserting, updating, and deleting its rows.

We have also seen that the ALTER query is capable of displaying the layout of columns (relations) of a table within databases. The UPDATE query can be used to change the attributes of the rows of a table.

There is no need to mention again, that UPDATE and ALTER, have many functions! In IT terms, both queries are highly useful. Their several good uses have already been mentioned several times above, both in theory and in the form of a table!

Both commands are part of SQL or Structured Query Language. SQL is a programming language that is used by many companies or organizations around the world to store large amounts of relational data as part of their daily grind.

You might not be aware, but there are many other SQL commands as well that go by different names but are not half as easy to remember as UPDATE and ALTER. Yes, these are two SQL, along with several others.

SQL queries help to control and manipulate data related to organizations, so it is a fact that they have a variety of functions. While the English meanings of both these SQL commands make them somewhat memorable, there are other more specialized SQL commands concerning databases. And only an IT expert can remember their names!

For eg., consider the SQL commands like Transact-SQL and FLUSH PRIVELEGES, whose functions cannot even be guessed upon hearing them for the first time! We will probably not find the meanings of these words anywhere in the English Dictionary, as they are purely SQL commands. In other words, we will probably have to consult an IT expert to ascertain their meanings.

Please remember that the above write-up is written with a view to entertain and also inform the reader about the many differences between both terms. At the start, the differences between UPDATE and ALTER were not at all obvious.

You could now use this article as a guide to help you understand the meaning of both terms, just to increase your knowledge and maybe even to impress your friends! Remember that the meaning of words UPDATE and ALTER as taken from the English Dictionary, have almost similar meanings.

Is this true? Yes, indeed it is! In simple English, the words ALTER and UPDATE both mean 'To change something'. However, there is a small difference between both words. ALTER generally means to make a slight change. On the other hand, UPDATE means to change something by adding new information. (Usually making it more modern/suitable)

Wikipedia informs us that Data is important for modern businesses from every aspect. It can be used for everything from lead generation to marketing. SQL, no doubt, is a powerful tool. SQL ensures that the data which is collected is used effectively.

SQL also helps fine-tune the process according to each individual company's needs. Now you know the power of SQL. Now you also know the effectiveness of UPDATE and ALTER both in English and in IT-related terms!

It is now an established fact that the meanings of both words really are worlds apart. In English, it means one thing, and in IT, quite another (at least with relation to SQL and databases). However, it really does help to know!

Does this information help you save face? Especially in front of a bunch of people who seemingly know better? Knowledge is a boon, as always. You can use it to impress a bunch of people who work in the IT Department of your company! You can also impress people you don't know with the knowledge of what you have read above.

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"Difference Between ALTER and UPDATE (in IT terms)." Diffzy.com, 2023. Mon. 25 Sep. 2023. <https://www.diffzy.com/article/difference-between-alter-and-update-in-it-1184>.

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