Difference Between PostgreSQL Varchar vs Text
PostgreSQL varchar vs text is where we will try to compare both the character datatypes provided in postgresql in order to observe the similarities and differences that exist between both of the datatypes. This will lead to a better choice of datatypes while designing our database, as the key factor for determining the performance of the database is the way in which we have structured it and set the datatypes of each of the columns of each of the table.
After reading this article, you will definitely be able to choose a suitable character data type for assigning to a particular column where you will be storing the string or text data. In this article, we will firstly look at the prerequisites, then go into the understanding of both the datatypes in general, and will observe the differences with the help of the comparison table and study the implementation and usage with the help of certain examples.
Prerequisites
Before going further with the article, please make sure that your machine should have the PostgreSQL server installed on it. Whether if it’s for Windows, Linux, or Mac OS platforms, refer this link for downloading them.
Head to Head Comparison Between PostgreSQL Varchar vs Text (Infographics)
Below are the top 5 differences between PostgreSQL Varchar vs Text:
Varchar vs Text Character Types
When you talk about the character types, they are the ones that help you to store characters in your database. There are three character types provided in PostgreSQL one is a character(n) also called char(n) for storing the characters having a fixed length. The other one is the character varying(n) also referred to as the varchar(n) where n is the number of characters that is character length. The last character type is the text which is unlimited in length. Note that while using the n in char(n) and varchar(n), n should be a positive integer value specifying the length of the column.
- Varchar(n): If we try to store the character value in this type of column and the length of the value is greater than that of the n value specified while creating the column in varchar(n) then it will throw an error in PostgreSQL saying that the character limit is exceeded specifying the limit of characters for that column in the error message. In case if all the values of characters being stored are spaces then they are truncated to a maximum value of length possessed by the column.
- TEXT: The text datatype helps to store the character values and is unlimited in length as there is no specification of n in it. The specification of n in varchar is optional in nature and when not specified the length of the column becomes unlimited and it works similar to that of text datatype. The performance of varchar(n) and text is the same when n i.e length is not specified in the declaration.
When you try to compare the two datatypes varchar(n) and text from the above discussion, we can see that there is no noticeable difference between the performance of both the datatypes when n is omitted in varchar. Hence, you can choose any one of them depending on your choice. However, if you are going to check the limit of the length of the column then you should go for varchar(n) specifying the appropriate and required length value as n.
PostgreSQL Varchar vs Text Comparison Table
The following table points out certain differences that exist and can be considered while choosing anyone from the two datatypes for your column.
|
Varchar |
Text |
| The syntax of the varchar data type is VARCHAR(n) where n stands for the maximum length of the column. | The syntax of text datatype is TEXT. |
| The length of the characters that can be stored inside the column with varchar datatype is limited when n is specified and unlimited when n is not specified. | The length of characters that can be stored inside the column with text datatype is unlimited. |
| When padding and spaces are mentioned they get truncated while execution. | The padding and spaces remain intact even while execution and storing. |
| When the value of n is not specified it is treated as infinity. | Already has unlimited length. No provision of specifying the n value. |
| One extra cycle is executed by query to check the length of the value being stored. | No cycle for length checking is done. |
Example of PostgreSQL Varchar vs Text
Let’s see, how we can store the data in both types of column datatypes with the help of an example. Here, we will first create a new table having both the columns with varchar (5) and text using the below statement –
CREATE TABLE varcharVStext(
column_iserial PRIMARY KEY,
sample_varchar VARCHAR (10),
sample_text TEXT
);
The execution of the above query statement gives the following output on the screen showing the message that the table creation is successful –
Now, we will try to insert a value in sample_varchar column which will be of the length greater than 10 using the following insert command –
INSERT INTO varcharVStext (sample_varchar, sample_text
VALUES
(
‘Let us insert a sample string in the column with limited length and varchar datatype’,
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'The column having text datatype can contain any string or any number of character values in it'
);
The execution of the above query statement gives the following output on the screen showing the error message that the value exceeds the limit length of the column –
If we now try to insert a value having the length of less than 0 characters as shown in the below statement, the statement will execute successfully giving no error as the value which is being inserted in the varchar column has a length less than the specified one.
INSERT INTO varcharVStext (sample_varchar, sample_text
VALUES
(
'sample',
'The column having text datatype can contain any string or any number of character values in it'
);
The execution gives the following output:
Conclusion
It is very crucial to choose the appropriate datatypes for your column in PostgreSQL database designing. Now, that you have learned about the similarities and the differences in both the character datatypes of varchar and text, you can select any one of them whichever fits your requirement. When using limited length data, the column should be assigned varchar(n) else you can go for anyone from them with varchar without n specification or even text datatype.
Recommended Articles
This is a guide to PostgreSQL Varchar vs Text. Here we discuss the PostgreSQL Varchar vs Text key differences with infographics and comparison table, respectively. You may also have a look at the following articles to learn more –
