PostgreSQL is one of the most robust Relational Database Management Systems. You can use SQL to create tables and store data in your databases.
Table of Contents
The data you would want to enter in your table would be of different types, some might be numbers, alphabet, special characters, etc. Hence, there are different data types that would act as guidelines for the different kinds of data to be entered in the fields.
Character types are the data types that are applicable to the fields that can hold character data. The different character types are PostgreSQL Varchar, Char, and Text data types.
In this article, you will come to know about the different character types supported by PostgreSQL. You will also come along with examples of usage of PostgreSQL Varchar, Char and Text data types.
Table of Contents
- What are Character Types?
- What are the Character Types in PostgreSQL?
- PostgreSQL Character Types: Overview
- PostgreSQL Char Data Type
- PostgreSQL Varchar Data Type
- PostgreSQL Text Data Type
- Conclusion
What are Character Types?
A data type specifies the guidelines regarding thetype of data that can be included in a table column or variable. It is a necessary and crucial phase in the design of a table. Character typesare data types that can be allocated to fields that will holdcharacter and string values.
A table with the wrong data types can cause problems such as poor query optimization, performance concerns, and data truncation.
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What are the Character Types in PostgreSQL?
The different character types supported by PostgreSQL are as follows:
- Character(n)
- Char(n)
- Character Varying(n)
- Varchar(n)
- Text
Out of the 5 character types, these can primarily be categorized into 3 types based on their similarities.
PostgreSQL Character Types: Overview
For having in-depth information about the three primary character types in PostgreSQL, you can move forward.
- PostgreSQL Char Data Type
- PostgreSQL Varchar Data Type
- PostgreSQL Text Data Type
1) PostgreSQL Char Data Type
Character data, often known as CHAR in PostgreSQL, represent the character type values. In other words, the PostgreSQL character data type is used when you want the variable to store a character of limited length. This length value can be specified as a parameter of the Char or Character type.
Char datatype is a fixed-length data type i.e., so if there is any remaining space then it is padded with blanks.
The following character data types can be used interchangeably.
- char(n)
- character(n)
A) Syntax
variable_nameCHAR(n)Orvariable_name CHARACTER(n)Here, variable_name is the name of the variable which should be of char datatype. And n represents the maximum length of a string which can be used as the variable_name.
B) Example
You have to assign the data type to a variable while creating a table. Hence, the datatype is used along with the CREATE statement.
CREATE TABLE Character_type ( Id serial PRIMARY KEY, X CHAR (1), Y CHAR (10) ); Here, you are creating a Character_type table, in which the variables are Id, X, and Y. Here, X and Y are of character types. And the length of any string assigned to X and Y can be a maximum of 1 character and 10 characters.
Now, while inserting values into the table:
INSERT INTO Character_type (X,Y) VALUES ('DPS', 'They provide the best education'), After executing the above command, you will get the following output mentioning, “the value is too long for type character varying (1)“. Since for both the variables, the character lengths exceed the 1 and 10 length limit.
To resolve the error you can enter the following command:
INSERT INTO Character_type (X,Y) VALUES ('A', 'Josephines'), After executing the above INSERT statement, 1 row will be inserted into the table with the values entered. And both X and Y have values within the maximum limit of the parameters mentioned.
2) PostgreSQL Varchar Data Type
The PostgreSQL Varchar data type is used to store characters of indefinite length based on the parameter n. It canstore a string up to 65,535 bytes long.
- In the PostgreSQL Varchar data type i. e. Varchar(n), n is used to denote the character length limit. If n is not specified, it defaults to a character of infinite length.
- PostgreSQL checks and throws an error if you try to get a longer string in a column specified by PostgreSQL Varchar(n).
- If the extra characters are assigned to a variable that is all whitespace in the PostgreSQL varchar data type, the whitespace is truncated to the maximum length (n) and the string is stored. This is the reason why the PostgreSQL Varchar data type is called the variable-length data type.
The PostgreSQL Varchar data types are:
- Varchar(n)
- Character Varying(n)
A) Syntax
variable_nameVARCHAR(n)Orvariable_name VARYINGING(n)Here, variable_name is the name of the variable which should be of char datatype. And n is the parameter of the PostgreSQL Varachar datatype which represents the length of a string that can be used as the variable_name.
B) Example
You have to assign the data type i.e, PostgreSQL Varchar to a variable while creating a table. Hence, the datatype is used along with the CREATE statement.
CREATE TABLE Varchar_type ( Id serial PRIMARY KEY, P VARCHAR(3), Q VARCHAR(13) ); Here, you are creating a Varchar_type table, in which the variables are Id, X, and Y. Here, X and Y are of character types. And the length of any string assigned to X and Y can be a maximum of 3 and 10 characters.
Now, while inserting values into the table:
INSERT INTO Text_type (X,Y) VALUES ('DEMS', 'They provide the best education'), After executing the above command, you will get the following output mentioning, “the value is too long for type character varying (1)“. Since for both the variables, the character lengths exceed the 3 and 13 length limit.
To resolve the error you can enter the following command:
INSERT INTO Varchar_type (X,Y) VALUES ('DPS', 'Best Education'), After executing the above INSERT statement, 1 row will be inserted into the table with the values entered. And Since for the Y variable, you have sent the varchar type with a maximum length of 13, so in ‘Best Education‘, it will automatically adjust, remove the space and save it.
3) PostgreSQL Text Data Type
The PostgreSQL Text data type is used to keep the character of infinite length. And it can hold a string with a maximum length of65,535bytes.
It is the same as the PostgreSQL Varchar data type, rather without any argument for mentioning the length of the character ie., the PostgreSQL Varchar Data Type without n is the same as the Text data type.
A) Syntax
variable_name TEXT Here, variable_name is the name of the variable which should be of TEXT datatype.
B) Example
You have to assign the data type to a variable while creating a table. Hence, the datatype is used along with the CREATE statement.
CREATE TABLE Text_type ( Id serial PRIMARY KEY, X TEXT, Y TEXT ); Here, you are creating a Text_type table, in which the variables are Id, X, and Y. Here, X and Y are of TEXT types. And the length of any string assigned to X and Y can be anything.
Now, while inserting values into the table:
INSERT INTO Text_type (X,Y) VALUES ('DPS', 'They provide the best education'), ('DEMS', 'They have great scope for extra-curricular activities'); After executing the above INSERT statement, 2 rows will be inserted into the table with the values entered.
For further information on PostgreSQL Varchar, Char, and Text data types, you can visit here.
Conclusion
This article illustrated the concept of different character types supported by PostgreSQL. You had an in-depth understanding of the PostgreSQL Varchar, Char, and Text datatypes.
Now, you can move forward and assign the different character types while creating tables.
Want to explore more about different clauses and statements while writing queries and creating tables in PostgreSQL? You can go through these articles.
- Working with PostgreSQL Subquery | A 101 Guide
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We hope you learned in-depth about the PostgreSQL Varchar, Char, and Text datatypes.
If you have any questions regarding the PostgreSQL Varchar, Char, and Text datatypes, do let us know in the comments section below. We’d be happy to help.
FAQs
PostgreSQL Varchar, Text and Character Data Types Made Easy | A 101 Guide - Learn | Hevo? ›
The CHAR is fixed-length character type while the VARCHAR and TEXT are varying length character types. Use VARCHAR(n) if you want to validate the length of the string ( n ) before inserting into or updating to a column. VARCHAR (without the length specifier) and TEXT are equivalent.
What is the difference between char and varchar and text in PostgreSQL? ›The CHAR is fixed-length character type while the VARCHAR and TEXT are varying length character types. Use VARCHAR(n) if you want to validate the length of the string ( n ) before inserting into or updating to a column. VARCHAR (without the length specifier) and TEXT are equivalent.
Should I use varchar or text PostgreSQL? ›Always use the text data type when storing strings in PostgreSQL. There is no performance benefit of using char(n) or varchar(n) . If you want to enforce a maximum length, use a check constraint which is more flexible and easier to change.
What is varchar data type in PostgreSQL? ›The PostgreSQL Varchar data type is used to store characters of indefinite length based on the parameter n. It can store a string up to 65,535 bytes long. In the PostgreSQL Varchar data type i. e. Varchar(n), n is used to denote the character length limit.
What is the difference between char varchar and text? ›CHAR items, which are fixed length, are the fastest to store and retrieve but can waste storage space. VARCHAR, a variable-length string, can be slower to store and retrieve but does not waste storage space. TEXT is a character BLOB that requires more storage space and I/O than the other two.
What is the advantage of CHAR vs VARCHAR? ›CHAR columns are fixed in size, while VARCHAR and VARCHAR(MAX) columns support variable-length data. CHAR columns should be used for columns that vary little in length. String values that vary significantly in length and are no longer than 8,000 bytes should be stored in a VARCHAR column.
When should I use text instead of VARCHAR? ›In most circumstances, VARCHAR provides better performance, it's more flexible, and can be fully indexed. If you need to store longer strings, use MEDIUMTEXT or LONGTEXT, but be aware that very large amounts of data can be stored in columns of these types.
What is the advantage of VARCHAR over text? ›A VARCHAR can be part of an index whereas a TEXT field requires you to specify a prefix length, which can be part of an index. VARCHAR is stored inline with the table (at least for the MyISAM storage engine), making it potentially faster when the size is reasonable.
Which encoding is best for Postgres? ›The character set support in PostgreSQL allows you to store text in a variety of character sets (also called encodings), including single-byte character sets such as the ISO 8859 series and multiple-byte character sets such as EUC (Extended Unix Code), UTF-8, and Mule internal code.
Should I use VARCHAR or varchar2? ›Difference Between varchar and varchar2: Varchar stands for a character string of variable length. Varchar and Varchar2 are data types used in databases to hold character strings for specific columns (fields). ORACLE has reserved these. Use varchar2 in instead of varchar if empty string and NULL are interchangeable.
What is the example of VARCHAR data? ›
VARCHAR is a variable length string data type, so it holds only the characters you assign to it. VARCHAR takes up 1 byte per character, + 2 bytes to hold length information. For example, if you set a VARCHAR(100) data type = 'Jen', then it would take up 3 bytes (for J, E, and N) plus 2 bytes, or 5 bytes in all.
What is the max size of VARCHAR in PostgreSQL? ›The notations varchar( n ) and char( n ) are aliases for character varying( n ) and character( n ) , respectively. If specified, the length must be greater than zero and cannot exceed 10485760. character without length specifier is equivalent to character(1) .
What is the max character VARCHAR in PostgreSQL? ›| PostgreSQL CHAR data type | PostgreSQL VARCHAR data type |
|---|---|
| The char data type cannot hold more than 255 characters. | The Varchar data type can hold up to 65535 characters. |
TRADEOFF #2 Since CHAR fields require less string manipulation because of fixed field widths, index lookups against CHAR field are on average 20% faster than that of VARCHAR fields.
What is the maximum length of VARCHAR? ›The length can be specified as a value from 0 to 65,535. The effective maximum length of a VARCHAR is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used.
What is the difference between string and text data type? ›Both a string and text field will hold information that you can freely write in. The major difference between the two fields is how many characters you can put in these fields. A string field has a limit of 255 characters, whereas a text field has a character limit of 30,000 characters.
What is the disadvantage of VARCHAR? ›1. Can lead to high space utilization if most of the values are close to maximum. 2. Positioning of VARCHAR column has to be done carefully as it has performance implications.
What are the disadvantages of CHAR data type? ›The only disadvantage of CHAR(n) or NCHAR(n) is its fixed length. When the length of data values varies widely from row to row, space is wasted.
What are the benefits of VARCHAR? ›If your data is VERY variable in length or may often be blank then the advantage from using varchar is that smaller overall rowlengths give more rows per page and therefore faster performance when retrieving/scanning multiple consecutive rows.
What type of data should not store in database? ›Finally, you shouldn't store credit card information in your database unless you absolutely need to. This includes credit card owner names, numbers, CVV numbers, and expiration dates. There is far too much risk involved.
Should I use VARCHAR as primary key? ›
It is perfectly acceptable to use a varchar column as the primary key. This is often the case when one uses a natural key that doesn't happen to be an integer. Keep in mind that even if you introduce a surrogate as the pimary key, you'll still need to create a unique constraint on product_id.
Can VARCHAR have numbers and letters? ›Also known as Variable Character, it is an indeterminate length string data type. It can hold numbers, letters and special characters. Microsoft SQL Server 2008 (and above) can store up to 8000 characters as the maximum length of the string using varchar data type.
What are the best VARCHAR values? ›The best value is the one that is right for the data as defined in the underlying domain. For some domains, VARCHAR(10) is right for the Name attribute, for other domains VARCHAR(255) might be the best choice.
How much TEXT is VARCHAR 255? ›VARCHAR(255) stores 255 characters, which may be more than 255 bytes.
What is the most popular PostgreSQL? ›pgAdmin is the most popular PostgreSQL GUI. It is purpose built for Postgres and supports all its features and operations. pgAdmin is open source and also supports Postgres derivative databases such as EDB Postgres Advanced Server. You can test it live here.
Which Postgres database is fastest? ›It's easy to use and designed to scale analytics (OLAP) & hybrid transactional workloads. Our team is excited to announce that Hydra is the fastest Postgres database for analytics.
What is the best data type for amount in Postgres? ›Numbers and numeric values. PostgreSQL includes a good range of numeric data types suitable for different scenarios. These include integers, floating points, arbitrary precision, and a special integer type with additional features called serial.
Why do we use varchar2 instead of CHAR? ›The difference between a CHAR and a VARCHAR is that a CHAR(n) will ALWAYS be N bytes long, it will be blank padded upon insert to ensure this. A varchar2(n) on the other hand will be 1 to N bytes long, it will NOT be blank padded. Using a CHAR on a varying width field can be a pain due to the search semantics of CHAR.
Which is better to use VARCHAR or NVARCHAR? ›For your application, nvarchar is fine because the database size is small. Saying "always use nvarchar" is a vast oversimplification. If you're not required to store things like Kanji or other crazy characters, use VARCHAR, it'll use a lot less space.
Where is VARCHAR used? ›Varchar datatype is used to store character strings of variable length. It uses static memory location. It uses dynamic memory location. Char takes 1 byte space for each character.
Does VARCHAR mean alphanumeric? ›
The CHAR and VARCHAR2 datatypes store alphanumeric data. Character data is stored in strings, with byte values corresponding to the character encoding scheme (generally called a character set or code page).
What is the primary key? ›A primary key is the column or columns that contain values that uniquely identify each row in a table. A database table must have a primary key for Optim to insert, update, restore, or delete data from a database table.
What is the text size in PostgreSQL? ›In PostgreSQL, the text data type is used to keep the character of infinite length. And the text data type can hold a string with a maximum length of 65,535 bytes.
What are the data types in PostgreSQL? ›The following types (or spellings thereof) are specified by SQL : bigint , bit , bit varying , boolean , char , character varying , character , varchar , date , double precision , integer , interval , numeric , decimal , real , smallint , time (with or without time zone), timestamp (with or without time zone), xml .
How to store large text in PostgreSQL? ›PostgreSQL allows us to store long text data in a column of a particular datatype - TEXT . We can specify the column definition right in the annotation. @Column(name = "doc_txt", columnDefinition = "text") private String docText; This allows us to work with long text in a "usual" way.
How many characters can VARCHAR 50 hold? ›Varchar(50) stores a maximum of 50 characters. Varchar(max) stores a maximum of 2,147,483,647 characters.
What is the character limit for PostgreSQL columns? ›Must begin with a letter or underscore. Must be less than the maximum length of 59 characters. Columns that exceed this limit will be rejected by PostgreSQL.
What is the difference between VARCHAR 8000 and VARCHAR Max? ›Varchar(8000) stores a maximum of 8000 characters. Varchar(max) stores a maximum of 2 147 483 647 characters. VARCHAR(MAX) uses the normal datapages until the content actually fills 8k of data as varchar(8000). When overflow happens, data is stored as old TEXT, IMAGE and a pointer is replacing the old content.
What is the default length of VARCHAR? ›VARCHAR is a variable-length character data type. The default length is 80, and the maximum length is 65000 octets. For string values longer than 65000, use Long Data Types. Values can include trailing spaces.
What is the minimum size of VARCHAR? ›This value is 255. The length to declare the host variable. The minimum number of characters that you can store in the VARCHAR column. Can range from 1 to 255 bytes but must be smaller than the maximum size of the VARCHAR.
How to store 10000 characters in SQL? ›
SQL Server Helper - Tip of the Day
The size (10000) given to the type 'varchar' exceeds the maximum allowed for any data type (8000). To avoid this error as well as to accomplish the requirement of having a maximum of 10,000 characters for a column, what you can do is to define the column as VARCHAR(MAX).
The string data types are CHAR , VARCHAR , BINARY , VARBINARY , BLOB , TEXT , ENUM , and SET .
How do you know if data is a string or number? ›- Integer. parseInt(String)
- Float. parseFloat(String)
- Double. parseDouble(String)
- Long. parseLong(String)
- new BigInteger(String)
A string in Python is a sequence of characters. In even simpler terms, a string is a piece of text. Strings are not just a Python thing. It's a well-known term in the field of computer science and means the same thing in most other languages as well.
What is the size of text in PostgreSQL? ›What is PostgreSQL Text datatype? In PostgreSQL, the text data type is used to keep the character of infinite length. And the text data type can hold a string with a maximum length of 65,535 bytes.
What is the difference between text and text [] in PostgreSQL? ›_text and text[] are interchangeable in PostgreSQL. Also text[][] is the same data type. In principle, there would be no problem in renaming _type to something else, but PostgreSQL forbids that in order to avoid confusion. Thanks for your answer!
What is the difference between CHAR and string data types? ›char is a primitive data type whereas String is a class in java. char represents a single character whereas String can have zero or more characters. So String is an array of chars.
What is the equivalent of varchar2 in PostgreSQL? ›Data type names often need translation. For example, in Oracle string values are commonly declared as being of type varchar2 , which is a non-SQL-standard type. In PostgreSQL, use type varchar or text instead.
What is the maximum number of characters in PostgreSQL text? ›If specified, the length must be greater than zero and cannot exceed 10485760. character without length specifier is equivalent to character(1) . If character varying is used without length specifier, the type accepts strings of any size. The latter is a PostgreSQL extension.
How is text stored in Postgres? ›PostgreSQL allows us to store long text data in a column of a particular datatype - TEXT . We can specify the column definition right in the annotation. @Column(name = "doc_txt", columnDefinition = "text") private String docText; This allows us to work with long text in a "usual" way.
What is the difference between BLOB and text in Postgres? ›
TEXT vs.
BLOB s are an alternative type of data storage that share matching naming and capacity mechanisms with TEXT objects. However, BLOB s are binary strings with no character set sorting, so they are treated as numeric values while TEXT objects are treated as character strings.
Data: Means facts collected together for some reference. Text: Simply the combination of letters or Characters.
Why char is faster than varchar? ›Searching is faster in CHAR as all the strings are stored at a specified position from the each other, the system doesnot have to search for the end of string. Whereas in VARCHAR the system has to first find the end of string and then go for searching.
What is the difference between character and string with syntax and example? ›The main difference between Character and String is that Character refers to a single letter, number, space, punctuation mark or a symbol that can be represented using a computer while String refers to a set of characters. In C programming, we can use char data type to store both character and string values.
Which is better VARCHAR or VARCHAR2? ›VARCHAR is reserved by Oracle to support distinction between NULL and empty string in future, as ANSI standard prescribes. VARCHAR2 does not distinguish between a NULL and empty string, and never will. If you rely on empty string and NULL being the same thing, you should use VARCHAR2 .
How to compare two database tables in PostgreSQL? ›- Click Schema Diff option, under Tools menu.
- You will see a form where you need to select Source and Target.
- Select server versions, source and target servers, and database/schema depending on your requirement.
- Click Compare to compare two databases/schemas.
Difference Between varchar and varchar2: Varchar stands for a character string of variable length. Varchar and Varchar2 are data types used in databases to hold character strings for specific columns (fields). ORACLE has reserved these. Use varchar2 in instead of varchar if empty string and NULL are interchangeable.