What Is A Blob (mysql) and how do i use it

[master_bacarra 0]

hey everyone! i just started using mysql so i could integrate it on my site. i'm trying to create a comment section and store the data on mysql. i've defined my table having a field type of varchar with max value 5000. but when i created it on phpmyadmin on my free hosting account, it said that the maximum value for a varchar is just 255. it said that i should use a blob. what is it and how can i access the data using php? i've searched from the net and it said that blob is used for images and document data. and i also found out that the data stored in a blob is a byte... so if i can use blob, how can i convert a text/string to a blob and vice versa. hmm... i'm confused...oh make that binary, not byte. sorry.

[WindAndWater 0]

Just consider blobs to be longer versions of varchars and use them in exactly the same way. In the phpAdmin or the mysqlAdmin (I don't remember which, as I usually do it manuall) you can change the type of field from varchar to blob. Do that, and then treat the rest exactly the same.

[Inspiron 0]

MySQL treat data unique. Hence there is a difference between Blob and Text. Text simply means a text string stored as orginal, not in binary, whereas a blob is a text string stored as a binary.

You can find more information about data types on the MySQL deocumentations.
http://dev.mysql.com/doc/refman/5.7/en/blob.html

[OpaQue 15]

BLOB and TEXT type as explained in MySQL Language Reference.

A BLOB is a binary large object that can hold a variable amount of data. The four BLOB types TINYBLOB, BLOB, MEDIUMBLOB, and LONGBLOB differ only in the maximum length of the values they can hold.
The four TEXT types TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT correspond to the four BLOB types and have the same maximum lengths and storage requirements. The only difference between BLOB and TEXT types is that sorting and comparison is performed in case-sensitive fashion for BLOB values and case-insensitive fashion for TEXT values. In other words, a TEXT is a case-insensitive BLOB.

[master_bacarra 0]

so i could use TEXT instead of BLOB in storing the comments? if so, how long is the maximum length for a TEXT in the free hosting accounts? and if ever i am to use a BLOB, how can i convert it to a non-binary form using php and vice versa?

[iGuest 3]

Blob vs. varchar vs. textWhat Is A Blob (mysql)

 A blob column type is used to store file contents, like images or pdf's, etc...Any file can go into a blob column type. The different blob types are all basically the same thing except they have different max sizes.

 

If you want to do something like comments, use column type 'text' and leave the maximum value blank. This will allow you to add any amount of text for the comment (for all realistic purposes).

 

I am making a comment system for my site now actually,

-reply by John