What Is String Data Type and Its Manipulative Functions

What Is Data String?

In general, a string data type consists of a series of letters and characters used to store text. 

However, the string type can also include numbers and symbols, which are treated as text. 

It's important to note that the string data type varies across different applications and programming languages, such as MySQL, Python, PHP, Java, C, and others.

In C programming, a string is a sequence of characters ending with a null character (\0).

In Java, a string is a set of one or more characters defined by the String keyword. To use the string data type, you enclose the text within double quotation marks (").

On the other hand, in MySQL, a string refers to a data type that can store characters, numbers, time, and dates, making it a combination of text elements. 

Then, in Python, strings are a frequently used data type that can be written using single quotes ('), double quotes ("), or triple quotes (''' or """).

String Data Type

String data types vary depending on the application and programming language. In this article, you will learn some string data types in MySQL. 

1.  TEXT/BLOB type

The first string type includes TEXT, BLOB, and their derivatives. The main differences between TEXT and BLOB are:

• TEXT string data is treated as a number string, while BLOB is treated as a binary string.
• TEXT string data has a standardized character set, while BLOB does not.
• The TEXT string data type sorts and compares data based on character sets, while BLOB does so based on stored data bytes as well as numeric values.

2.  String Data Types Other than TEXT/BLOB

In addition to TEXT and BLOB, strings have other data types, including:

• VARCHAR Data Type: This data type stores data based on the number of characters entered. VARCHAR has one data byte of 255.
• CHAR Data Type: A data type similar to VARCHAR, but with fixed storage. This data type has 255 bytes of data.
• BINARY Data Type: This data type is similar to CHAR, but the data is stored in bytes or binary form. For example, if data has 70 characters, then 70 characters are stored.
• VARBINARY Data Type: This data is similar to BINARY, but VARBINARY has no fixed byte storage.
• ENUM Data Type: ENUM data can only read data that has been entered. For example, if you have entered data A, B, BC, and BD, it will be written as ENUM('A', 'B', 'BC', 'BD'). If you enter new data BE, then the BE data cannot be read.
• SET Data Type: This data type is similar to ENUM but has a byte size of N (the amount of data entered, N=1 byte).

Some String Data Manipulation Functions

String data manipulation functions vary by programming language. Below are some functions for C, Python, and PHP.

1.  String Data Manipulation Functions in C Programming

C programming has a wide variety of string manipulation functions that can be used as needed, here are the following:

• Strcat() function: Append a string from the back.
• The strcpy() function: Copies a string from one variable to another.
• Function strlen(): Calculates the length of a string.
• The strcmp() function: Compares one string to another. This function returns 0 if the two strings being compared are equal.
• Strchr() function: Searches for characters within a string.
• Strstr() function: Searches for text within a string.

2.  String Data Manipulative Functions in Python

Python has several string data manipulation functions that can be used. Here are the Python string data type:

• Slicing strings: Indexing and slicing strings.
• Computing the length of a string: Calculates the length of a string using the len() function.
• Checking the start character of a string: Checks the startswith() to test for the start character of a string.
• Checking the end character of a string: The string.endswith() function can be used to check the end character of a string.
• Concatenate strings: Uses the + operator to concatenate strings.

3.  String Data Manipulation Functions in PHP

There are several string data manipulation functions in PHP that you can use, including:

• The strlen function: Computes the length of a string.
• Strtolower function: Converts a string to lowercase.
• Strtoupper function: Converts strings to capital letters.
• Substr function: Retrieves a specific part of a string
• The strpos function: Finds the first position of a substring in a string.
• The str_replace function: Replaces one part of a string with another.
• Sprintf function: Formats a string with the format specification to add certain settings, such as decimal and size limitations.
• Explode function: Splits the string into an array according to the specified delimiter.
• Implode function: Concatenates array elements into a string according to the specified delimiter.
• Trim, ltrim, and rtrim functions: Removes spaces at a string's beginning, end, or both ends.
• Pad function: Adds spaces to the string so that the string length matches the specified size.

How to Concatenate Strings

Note that the way you concatenate string data types may differ depending on the application and programming language you are using.

If you are using the Python programming language, you can concatenate strings with a plus sign (+) or a comma (,).

If you are using Java, you can concatenate strings with a plus sign (+) with no limit on string length. However, string creation is limited by the amount of RAM your computer has available.