What are different TEXT data types in MySQL. What is difference between TEXT and VARCHAR ?
Câu trả lời
In MySQL, there are several TEXT data types designed to accommodate different sizes of text data. These include:
TINYTEXT: Stores very small text strings up to 255 characters, ideal for tiny pieces of text like status messages or flags[7].
TEXT: A standard type for text storage, capable of holding up to 65,535 characters (around 64KB), suitable for paragraphs or short articles[7].
MEDIUMTEXT: Holds larger blocks of text, up to 16,777,215 characters (about 16MB), making it fit for long articles, small books, or extensive logs[7].
LONGTEXT: The biggest text data type in MySQL, storing up to 4,294,967,295 characters (approximately 4GB), intended for very large texts such as complete books, comprehensive documentation, or datasets with significant text[7].
The primary difference between TEXT and VARCHAR data types in MySQL lies in their storage capabilities, performance implications, and use cases.
Storage and Performance: VARCHAR is suitable for storing variable-length strings. It's more efficient for shorter strings because it only consumes storage space for the actual data length plus one or two bytes for the length prefix. The maximum length for VARCHAR columns is typically 255 characters but can be extended up to 65,535 characters in MySQL 5.0.3 and later, albeit with potential performance implications[2]. TEXT types, on the other hand, are designed for handling longer strings that exceed the maximum length of VARCHAR, up to a theoretical limit of 65,535 bytes (64 KB) for TEXT, with MEDIUMTEXT and LONGTEXT allowing for even larger amounts of data. Unlike VARCHAR, TEXT columns are stored outside of the row data and are subject to different storage and retrieval mechanisms, which can affect performance[2].
Indexing and Sorting: VARCHAR can be fully indexed, allowing for efficient searching and sorting operations over the entire length of the string. TEXT columns, however, can only be indexed up to a specified length, and the full length of the string cannot be used for sorting. This limitation can have perfo...
