Mysql array type php

Data type of array in mysql

I have a variable of type array and I want to store it as it is in database(mysql) and when I apply tinyblob that I usually use in java for display it return abnormal output. So what is the correct datatype for the array in php.

$countryGoup=array("USA","FRANCE","GERMANY","BRITAIN"); 

1 Answer 1

1) use a SET datatype if the values are few and fixed

You define the column in the CREATE TABLE statement as SET(‘USA’, ‘France’, ‘Germany’, . ) NOT NULL (not null optional), and use queries like:

INSERT INTO myTable SET countries="USA,Germany"; 

2) use a lookup table with a foreign reference

So you define a countries table:

id_country|name ----------+----------- 1 |USA 2 |Germany 3 |France 

and define a pivot table that links your main object (f.ex. «users») to the countries, thus esabilishing a many-to-many relationship.

F.ex., a users_countries table would link users table to countries table in this way:

id_user|id_country ------------------ 1 |1 1 |2 2 |1 

In this example, user 1 is linked to countries with id 1 and 2 (USA and Germany), user 2 is linked to USA only, and so on

3) use a comma-separated string, or other separators, or serialize the array

This involves using the server-side language (in your case PHP) to concat the values with some separator (such as comma , or pipe | ):

$countries = array("USA", "Russia", "Iran"); $countriesString = implode (",", $countries); // $countriesString = "Usa,Russia,Iran" $query = "INSERT INTO mytable SET countries = '" . $countriesString . "'"; 

(Note: the string value is not escaped for example purpose, but it is not a good practice)

When you retrieve the value from the db, you retrive the string you put into, and obtain again an array with $array = explode(«,», $retrievedValueFromDb) , providing the same separator.

4) Retrieve values find_in_set() MySQL function

You can rely also on the find_in_set(needle, field) function, that returns an integer greater than zero if the string is present in a comma-separated value field.

So if you use approach 1) and have a string field like «USA,Germany» , you can obtain the columns in which USA is present by using:

SELECT * FROM myTable WHERE find_in_set('USA', countries) <> 0 

Approach 1) works if you have few fixed values, also very easy on queries. Downside is that you are limited to 64 values, that the values must be fixed, and the cannot contain a comma (,) as its used as a separator.

Approach 2) is the most standardized and correct, it’s also normalized and query-efficient

Approach 3) is easy but requires extra processing and is not so easy for SQL

As stated elsewhere, there is no «array» datatype in the dbms, you have to use some workaround.

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Array Data Types in MySQL

An example of linking a table to another table involves linking user 1 to countries with id 1 and 2 (USA and Germany) and user 2 to USA only. One way to serialize the array is by using a comma-separated string or other separators. To do this, concatenate the values using a server-side language like PHP with a specific separator like a comma or pipe. When retrieving the value from the database, retrieve the string and obtain an array with the same separator. If you need to add a field with a default value, how can you do this?

Data type of array in mysql

I possess an array variable that requires storage in its original form in a MySQL database. However, upon invoking the tinyblob function that I typically use in Java for display purposes, it returns abnormal output. What is the appropriate PHP data type for this array?

$countryGoup=array("USA","FRANCE","GERMANY","BRITAIN"); 

1) use a SET datatype if the values are few and fixed

In the CREATE TABLE statement, you specify the column as SET(‘USA’, ‘France’, ‘Germany’, . ) NOT NULL with an optional «not null» constraint. After this, you can execute queries such as:

INSERT INTO myTable SET countries="USA,Germany"; 

2) use a lookup table with a foreign reference

So you create a table named countries .

id_country|name ----------+----------- 1 |USA 2 |Germany 3 |France 

Create a pivot table that establishes a many-to-many connection between your primary entity (e.g. «users») and various countries.

For instance, one table labeled as users_countries would establish a connection between the users table and the countries table, using the following method:

id_user|id_country ------------------ 1 |1 1 |2 2 |1 

The given instance showcases that user 1 is associated with countries having id 1 and 2, namely, USA and Germany respectively. On the other hand, user 2 is only connected with USA, while the rest of the users have their own distinct linkages.

3) use a comma-separated string, or other separators, or serialize the array

The process entails utilizing the server-side programming language (in this case PHP) to merge the values with a designated separator (e.g., comma , or pipe | ).

$countries = array("USA", "Russia", "Iran"); $countriesString = implode (",", $countries); // $countriesString = "Usa,Russia,Iran" $query = "INSERT INTO mytable SET countries = '" . $countriesString . "'"; 

It is worth noting that the string value is not escaped in the example provided for illustrative purposes only, and should not be considered a good practice.

Upon retrieving the value from the database, the string that was initially inputted is also retrieved, and an array containing $array = explode(«,», $retrievedValueFromDb) is obtained once more, utilizing the same separator.

4) Retrieve values find_in_set() MySQL function

You can also depend on the find_in_set(needle, field) method to give you a positive integer value indicating the presence of a string in a field with a comma-separated value.

If you adopt the first method and your field is a string containing «USA,Germany» , you can retrieve the columns where USA appears by utilizing the following technique:

SELECT * FROM myTable WHERE find_in_set('USA', countries) <> 0 

One possible method is suitable when dealing with a small number of constant values and is also efficient in terms of querying. However, it has a drawback of being restricted to a maximum of 64 values, necessitating them to be fixed, and prohibiting the inclusion of commas as they serve as separators.

The second approach is not only standardized and correct, but it is also normalized and efficient for querying.

The third approach is not SQL-friendly and demands additional processing, although it is straightforward.

It should be noted that the dbms does not offer a data type called «array», therefore a workaround must be implemented.

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What is DC2Type array datatype in mysql

While working with Symfony2 and doctrine2, I have come across an unusual datatype known as DC2Type:array, which is used to store some Symfony2 Roles. Upon inspection, it appears to be a serialized PHP array where ‘a’ represents the total number of elements and ‘i’ represents the array index.

The value looks like this:

Can you provide me with the identity of this data type?

What is the meaning of the following identifier?

Despite scouring through the internet, I have not come across any beneficial information.

While browsing, I came across a cookbook entry at http://readthedocs.org/docs/doctrine-orm/en/2.0.x/cookbook/mysql-enums.html, but I wasn’t able to determine its source.

The column type is not data type. It is important to note that DC2Type:array is merely a comment associated with this field, as the type is actually LONGTEXT.

Doctrine employs the field’s comment section to store metadata of the column. Due to the unavailability of array storage in Mysql, DC2Type:array is utilized by Doctrine as a comment to facilitate unserialization of the content.

Take a look at the link below.

The issue can be found at the following GitHub URL: https://github.com/doctrine/dbal/issues/1614.

By following the provided link, it can be observed that the remark DC2Type:enumvisibility denotes a flag that signifies whether the record is visible or not. It is not a novel data type, but rather a supportive technique at the database level, which is considered a custom data type by Doctrine.

The given data is a PHP array in serialized format. Each item value in the array is referred to by the s: symbol, which denotes its size or length.

The number of characters in the string ROLE is 32.

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MySql array type and default value

I require a field to be added with a predetermined value.

`setting_notification` = 'a:2:' ALTER TABLE app_users ADD setting_notification tinytext COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)' 

ALTER TABLE app_users ADD setting_notification LONGTEXT CHARACTER SET utf8 DEFAULT 'a:2:' COMMENT '(DC2Type:array)' 

 [Err] 1101 - BLOB, TEXT, GEOMETRY or JSON column 'setting_notification' can't have a default value 

ALTER TABLE app_users ADD setting_notification tinytext DEFAULT "a:2:" COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)' 

[Err] 1101 - BLOB, TEXT, GEOMETRY or JSON column 'setting_notification' can't have a default value 

mysql> SELECT VERSION(); +-------------------------+ | VERSION() | +-------------------------+ | 5.7.16-0ubuntu0.16.04.1 | +-------------------------+ 1 row in set (0,01 sec) 

Instead of using tinytext, why not utilize varchar and add a default value?

ALTER TABLE app_users ADD setting_notification varchar(255) DEFAULT "a:2:" COLLATE utf8_unicode_ci NOT NULL COMMENT '(DC2Type:array)' 

Storing arrays in MYSQL? — Database Administrators, 1. Simple arrays: MySQL doesn’t really have an array datatype — the closest thing they have is the SET datatype, the functionality of which is very …

Is there any array data type in MySQL like in PostgreSQL?

Is there a way to perform the equivalent of obtaining a list of integers within a range in MySQL? I require store arrays integers that fall within a MySQL database range.

 CREATE TABLE tictactoe ( squares integer[3][3] ); 

My requirement is to store matrices of size 20×6, but I don’t wish to create a table with 120 columns. This field doesn’t require any querying, and I only need to store and retrieve complete matrices.

The feature does not exist currently. Although there is a worklog available for it, no advancement has been made towards its implementation.

To achieve this, you can either use several fields (in your case, 9) or consolidate the integers into a bigger data type, such as a blob.

Save the numbers in text format by utilizing suitable delimiters. For instance, to store numbers 1 through 9, save them in text format as 1-2-3-4-5-6-7-8-9, where ‘#’ is used as the delimiter in the string and can be utilized to extract the required numbers.

Unfortunately, I cannot provide a definitive answer without more information about the task at hand. Simply put, there is no clear answer without context.

How can I use array data type in mysql?, There is no data type to store an array in MySQL. but you can convert your array to JSON and store it in the table and convert it back to an array when …

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