Maximum length for MySQL type text
I’m creating a form for sending private messages and want to set the maxlength value of a textarea appropriate to the max length of a text field in my MySQL database table. How many characters can a type text field store? If a lot, would I be able to specify length in the database text type field as I would with varchar?
@Marc B Never underestimate a user’s ability to paste vast amounts of garbage into a private text message field.
@Binozo Yeah, server side (Java/JavaEE/JakartaEE: preconditions, JSF validators, Bean Validation). Client side validation equals to nothing.
8 Answers 8
TINYBLOB, TINYTEXT L + 1 bytes, where L < 2^8 (255 Bytes) BLOB, TEXT L + 2 bytes, where L < 2^16 (64 Kilobytes) MEDIUMBLOB, MEDIUMTEXT L + 3 bytes, where L < 2^24 (16 Megabytes) LONGBLOB, LONGTEXT L + 4 bytes, where L < 2^32 (4 Gigabytes) L is the number of bytes in your text field. So the maximum number of chars for text is 2 16 -1 (using single-byte characters). Means 65 535 chars(using single-byte characters).
UTF-8/MultiByte encoding: using MultiByte encoding each character might consume more than 1 byte of space. For UTF-8 space consumption is between 1 to 4 bytes per char.
@fyr- Here what is means for L + 2 bytes, where L < 2^16 ? Could you please define it a bit more ? Other wise you can tell me how many chars we can store in text field ? Please.
@J.J. L is the number of chars and the number of chars need to be less than 2 to the power of 16. 2^16 = 65536. So you might enter 65535 chars which consume 65535 bytes + 3 bytes = 65 538 bytes per full filled field.
Note that the size limits are in bytes. So if you use multi-byte characters, you don't get 2^16 characters in a TEXT column, you get however many characters you can store in 2^16 bytes.
What Bill Karwin said. BYTES, NOT CHARACTERS. A character may use 4 bytes to store with the given encoding (like 💩 in UTF-8).
| Type | Approx. Length | Exact Max. Length Allowed |
|---|---|---|
| TINYTEXT | 256 Bytes | 255 characters |
| TEXT | 64 Kilobytes | 65,535 characters |
| MEDIUMTEXT | 16 Megabytes | 16,777,215 characters |
| LONGTEXT | 4 Gigabytes | 4,294,967,295 characters |
"Exact Max. Length Allowed" = "Approx. Length" in bytes - 1
Note: If using multibyte characters (like Arabic, where each Arabic character takes 2 bytes), the column "Exact Max. Length Allowed" for TINYTEXT can hold be up to 127 Arabic characters (Note: space, dash, underscore, and other such characters, are 1-byte characters).
TINYTEXT: 256 bytes
TEXT: 65,535 bytes
MEDIUMTEXT: 16,777,215 bytes
LONGTEXT: 4,294,967,295 bytes
TINYTEXT 256 bytes TEXT 65,535 bytes ~64kb MEDIUMTEXT 16,777,215 bytes ~16MB LONGTEXT 4,294,967,295 bytes ~4GB TINYTEXT is a string data type that can store up to to 255 characters.
TEXT is a string data type that can store up to 65,535 characters. TEXT is commonly used for brief articles.
LONGTEXT is a string data type with a maximum length of 4,294,967,295 characters. Use LONGTEXT if you need to store large text, such as a chapter of a novel.
side note: I think 4.3 billion characters would be more of an entire book than just a chapter ^^ Assuming 80 characters per line and 50 lines per page (both of which are pretty generous and would probably be an a4-sized book), that still equals about 1 millIion pages. Would be a pretty fuckin' long chapter 😀 MEDIUMTEXT would equal about 4000 pages with the same numbers, which would still be a lot, but normal TEXT would be only about 16 pages, which might be too short.
You shouldn't need to concern yourself with limiting it, it's automatically broken down into chunks that get added as the string grows, so it won't always blindly use 64k.
How many characters can a type text field store?
According to Documentation You can use maximum of 21,844 characters if the charset is UTF8
If a lot, would I be able to specify length in the db text type field as I would with varchar?
You dont need to specify the length. If you need more character use data types MEDIUMTEXT or LONGTEXT. With VARCHAR, specifieng length is not for Storage requirement, it is only for how the data is retrieved from data base.
TEXT is a string data type that can store up to 65,535 characters. But still if you want to store more data then change its data type to LONGTEXT
ALTER TABLE name_tabel CHANGE text_field LONGTEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;
Numeric Type Storage Requirements
Data Type Storage Required TINYINT 1 byte SMALLINT 2 bytes MEDIUMINT 3 bytes INT, INTEGER 4 bytes BIGINT 8 bytes FLOAT(p) 4 bytes if 0 Values for DECIMAL (and NUMERIC) columns are represented using a binary format that packs nine decimal (base 10) digits into four bytes. Storage for the integer and fractional parts of each value are determined separately. Each multiple of nine digits requires four bytes, and the “leftover” digits require some fraction of four bytes. The storage required for excess digits is given by the following table.
Date and Time Type Storage Requirements For TIME, DATETIME, and TIMESTAMP columns, the storage required for tables created before MySQL 5.6.4 differs from tables created from 5.6.4 on. This is due to a change in 5.6.4 that permits these types to have a fractional part, which requires from 0 to 3 bytes.
Data Type Storage Required Before MySQL 5.6.4 Storage Required as of MySQL 5.6.4 YEAR 1 byte 1 byte DATE 3 bytes 3 bytes TIME 3 bytes 3 bytes + fractional seconds storage DATETIME 8 bytes 5 bytes + fractional seconds storage TIMESTAMP 4 bytes 4 bytes + fractional seconds storage As of MySQL 5.6.4, storage for YEAR and DATE remains unchanged. However, TIME, DATETIME, and TIMESTAMP are represented differently. DATETIME is packed more efficiently, requiring 5 rather than 8 bytes for the nonfractional part, and all three parts have a fractional part that requires from 0 to 3 bytes, depending on the fractional seconds precision of stored values.
Fractional Seconds Precision Storage Required 0 0 bytes 1, 2 1 byte 3, 4 2 bytes 5, 6 3 bytes For example, TIME(0), TIME(2), TIME(4), and TIME(6) use 3, 4, 5, and 6 bytes, respectively. TIME and TIME(0) are equivalent and require the same storage.
For details about internal representation of temporal values, see MySQL Internals: Important Algorithms and Structures.
String Type Storage Requirements In the following table, M represents the declared column length in characters for nonbinary string types and bytes for binary string types. L represents the actual length in bytes of a given string value.
Data Type Storage Required CHAR(M) The compact family of InnoDB row formats optimize storage for variable-length character sets. See COMPACT Row Format Characteristics. Otherwise, M × w bytes, Saved searches
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A handy PHP class for printing fixed-width text tables.
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dan-da/texttable-php
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README.md
A handy PHP class for printing fixed-width text tables.
There is also a class for printing human-friendly markdown tables.
Let's see a couple examples, shall we?
Example Price History Report ( from bitprices )
+------------+------------------+-----------+-------------+----------------+---------------+----------+ | Date | BTC Amount | USD Price | USD Amount | USD Amount Now | USD Gain | Type | +------------+------------------+-----------+-------------+----------------+---------------+----------+ | 2011-11-16 | 500000.00000000 | 2.46 | 1230000.00 | 189905000.00 | 188675000.00 | purchase | | 2011-11-16 | -500000.00000000 | 2.46 | -1230000.00 | -189905000.00 | -188675000.00 | sale | | 2013-11-26 | 0.00011000 | 913.95 | 0.10 | 0.04 | -0.06 | purchase | | 2013-11-26 | -0.00011000 | 913.95 | -0.10 | -0.04 | 0.06 | sale | | 2014-11-21 | 0.00010000 | 351.95 | 0.04 | 0.04 | 0.00 | purchase | | 2014-12-09 | 0.00889387 | 353.67 | 3.15 | 3.38 | 0.23 | purchase | | 2015-06-05 | 0.44520000 | 226.01 | 100.62 | 169.09 | 68.47 | purchase | | 2015-06-07 | 0.44917576 | 226.02 | 101.52 | 170.60 | 69.08 | purchase | | 2015-10-17 | 0.00010000 | 270.17 | 0.03 | 0.04 | 0.01 | purchase | | 2015-11-05 | 0.00010000 | 400.78 | 0.04 | 0.04 | 0.00 | purchase | | Totals: | 0.90356963 | | 205.40 | 343.19 | 137.79 | | +------------+------------------+-----------+-------------+----------------+---------------+----------+ Days of the week. From ./example-weekdays2.php
+-----------+--------+---------+----------+ | Day | Abbrev | Initial | Position | +-----------+--------+---------+----------+ | Sunday | Sun | S | 0 | | Monday | Mon | M | 1 | | Tuesday | Tue | T | 2 | | Wednesday | Wed | W | 3 | | Thursday | Thu | T | 4 | | Friday | Fri | F | 5 | | Saturday | Sat | S | 6 | +-----------+--------+---------+----------+ You can install with composer.
$ cd yourproject $ composer require dan-da/texttable-php require_once 'path/to/vendor/autoload.php'; Or just drop into your project.
There are no dependencies!
Simply include texttable.class.php from any PHP file and use it!
Here's a trivial example that prints info about the days of the week:
strftime('%A', $timestamp), 'Abbrev' => strftime('%a', $timestamp), 'Initial' => strftime('%A', $timestamp)[0], 'Position' => $i ]; $timestamp = strtotime('+1 day', $timestamp); > echo " [ Table with header from first row keys. similar to db result set. ]\n"; echo texttable::table( $data ); About
A handy PHP class for printing fixed-width text tables.
Изменение ширины таблицы средствами php
Всем привет, уважаемые знатоки, подскажите в чем может быть проблема.
На странице php автоматически формируется таблица, в коде html прописано жесткое ограничение ширины столбцов, после окончания формирования таблицы последний столбец уходит за границы страницы - текст не переносится.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
form method="post" action="" class="rf"> input type="text" style="width:300" name="tbd" size="20" value=""/>br> input type="submit" style="width:300" name="cmd0" value="Найти по торговому наименованию">(Не менее 5 символов)br> input type="submit" style="width:300" name="cmd1" value="Найти по описанию">(Не менее 7 символов)br> /form> table width=99% border=1 font size = "1"> col width=15%> col width=15%> col width=5%> col width=5%> col width=9%> col width=5%> col width=55%> th>Наименование/> th>Изготовитель/> th>Цена/> th>Срок/> th>Штрих-код/> th>Остаток/> th>Описание/> if($_POST['cmd0']){ $file_name = "rozn.txt"; $var = $_POST['tbd']; if(strlen($var) > 4)< $var = strtolower($var); $data = file( $file_name ); foreach( $data as $value ): $value = explode( ";", $value ); // сдесь проверка условия $zn = $value[0]; $zn = strtolower($zn); $pos = strpos($zn, $var); if ($pos === false) < //echo 'Данные не обнаружены'; >else < ?>tr> td>=$value[0]?>/td> td>=$value[1]?>/td> td>=$value[2]?>/td> td>=$value[3]?>/td> td>=$value[4]?>/td> td>=$value[5]?>/td> td>=$value[6]?>/td> /tr> } // Сравнение, == endforeach; } } // вторая кнопка ******************************************************************* if($_POST['cmd1']){ $file_name = "rozn.txt"; $var = $_POST['tbd']; if(strlen($var) > 6)< $var = strtolower($var); $data = file( $file_name ); foreach( $data as $value ): $value = explode( ";", $value ); // сдесь проверка условия $zn = $value[6]; $zn = strtolower($zn); $pos = strpos($zn, $var); if ($pos === false) < //echo 'Данные не обнаружены'; >else < ?>tr> td>=$value[0]?>/td> td>=$value[1]?>/td> td>=$value[2]?>/td> td>=$value[3]?>/td> td>=$value[4]?>/td> td>=$value[5]?>/td> td>=$value[6]?>/td> /tr> } // Сравнение, == endforeach; } } ?> /table> /td> /tr> /table> // почему то с этим столбцы формируются более стабильно, а последний все равно уезжает. exit; ?>