TEXT data objects, as their namesake implies, are useful for storing long-form text strings in a MySQL
database. The four TEXT data object types are built for storing and displaying substantial amounts of
information as opposed to other data object types that are helpful with tasks like sorting and searching
columns or handling smaller configuration-based options for a larger project. The different TEXT objects
offer a range of storage space from 1 byte to 4 GB and are not designed for storing computational
values. It’s common to see these used to store product descriptions for a sales site, property summaries
for realty database, and long-form article text on a news website. TEXT objects are best used when
VARCHAR and other string-based data objects are insufficient to handle storing the desired amount of
information. However, the smallest TEXT type, TINYTEXT, shares the same character length as VARCHAR.
TEXT objects differentiate themselves from other string storage types by removing the requirement to
specify a storage length, not stripping bytes when selected, and do not pad unused character space for
efficient disk storage. Since TEXT objects are not stored in the server’s memory, they require data
overhead for retrieval. The following sizes assume the database is using the UTF-8 encoding.
TINYTEXT: 255 characters - 255 B
The TINYTEXT data object is the smallest of the TEXT family and is built to efficiently store short
information strings. This type can store up to 255 bytes (expressed as 2^8 -1) or 255 characters and
requires a 1 byte overhead. This object can be used to store things like short summaries, URL links, and
other shorter objects. TINYTEXT shines over VARCHAR when storing data that’s under 255 characters
with an inconsistent length and no need to be used for sorting criteria.
TEXT: 65,535 characters - 64 KB
The standard TEXT data object is sufficiently capable of handling typical long-form text content. TEXT
data objects top out at 64 KB (expressed as 2^16 -1) or 65,535 characters and requires a 2 byte
overhead. It is sufficiently large enough to hold text for something like an article, but would not be
sufficient for holding the text of an entire book.
MEDIUMTEXT: 16,777,215 - 16 MB
The MEDIUMTEXT data object is useful for storing larger text strings like white papers, books, and code
backup. These data objects can be as large as 16 MB (expressed as 2^24 -1) or 16,777,215 characters
and require 3 bytes of overhead storage.
LONGTEXT: 4,294,967,295 characters - 4 GB
The LONGTEXT data object is for use in extreme text string storage use cases. It is a viable option when
the MEDIUMTEXT object is not big enough. Computer programs and applications often reach text
lengths in the LONGTEXT range. These data objects can be as large as 4 GB (expressed as 2^32 -1) and
store up to 4,294,967,295 characters with 4 bytes of overhead storage,
TEXT vs. BLOB
BLOBs are an alternative type of data storage that share matching naming and capacity mechanisms
with TEXT objects. However, BLOBs are binary strings with no character set sorting, so they are treated
as numeric values while TEXT objects are treated as character strings. This differentiation is important
for sorting information. BLOBs are used to store data files like images, videos, and executables.
Usage Notes
Using TEXT fields for select and search queries will incur performance hits because the server will call
the objects individually and scan them during the query instead of paging data stored in the memory.
Enabling strict SQL will enforce the maximum character lengths and truncate any entered data that
exceeds those limits.
TEXT columns require an index prefix length and can’t have DEFAULT values, unlike CHAR and VARCHAR
objects.
Estimating size by word count: assume average English word is 4.5 letters long and needs 1 extra
character for spacing. Example, a site that consists of 500 word articles would use about 2,750
characters on average for the article text data. TINYTEXT’s 255 character capacity is insufficient for this
use case, while TEXT’s 65535 character capacity offers storage for articles that hit over 11,900 words
based on the average criteria.