I optimized my table with an option in phpmyadmin as it was flashing below. I was using LONGTEXT type for my column file_data. Now, for some reason, huge values are not being entered into this column. It gives NULL. What can I do and do I have to change the data type to ENUM as suggested by propose table structure?
Thanks,
JJ
I think that you are trying to insert long text in the field.
The only option is to make (change it back) field as text field.
Please run following SQL, (replace the table name in SQL)
ALTER TABLE <<your table name>> CHANGE file_data file_data TEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL ;
Related
I am trying to convert a specific column in a table on my DB from latin1 character set with collation latin1_swedish_ci to utf8 with collation utf8_unicode_ci.
COLUMN: description, type: longtext, default not null
I tried the following commands on the column:
ALTER TABLE sample MODIFY description LONGBLOB NOT NULL ;
ALTER TABLE sample MODIFY description LONGTEXT CHARACTER SET utf8 NOT NULL COLLATE utf8_unicode_ci;
I also tried to alter the encoding WITHOUT changing to binary first. But the characters ended up being re-encoded incorrectly by the server.
And keep getting an error regarding some characters:
Error Code: 1366. Incorrect string value: '\x92t hav...' for column 'longDesc' at row 803
It seems like some of the character in my table aren't converting correctly.
How can I fix this issue?
\x92 implies that you have latin1 in the table now. The second ALTER is claiming that the bytes are in utf8 encoding. Hence, the error message.
Case 1: You need to change the LONGTEXT to utf8 because you plan to add rows with text that cannot be encoded in latin1.
For this case, ALTER TABLE sample CONVERT TO CHARACTER SET utf8; -- converts all CHAR/TEXT columns in the table.
ALTER TABLE sample MODIFY description ... CHARACTER SET utf8; -- converts the one column.
Case 2: The rest of the system is thinking utf8 and is confused by this column.
Well, I don't think it is confused. Conversions happen as needed.
I'm on a MYSQL database attempting to alter my table encoded in latin1 to UTF-8. The tables name is Journalist that has 12 columns listed as varchar with max length of 3000. This is the sql i'm running.
ALTER TABLE `journalist` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
The error I'm receiving
Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs
Do I have to alter the size of the table before I run this conversion query?
and/or how I might accomplish this encoding alteration otherwise?
I did what #Wrikken suggested. I deleted my table and lowered varchar's max_length attributes to 1500 from 3000. I then ran this SQL on my new empty table
ALTER TABLE `table_name` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
from here, I repopulated it with my backup table, using a script.
To answer the question:
Lower varchar max_length limits
Or change varchar fields to LONGTEXT, or BLOBS
I am using Django on Bluehost. I created a form for user generated input, but unicode inputs from this form fails to be stored or displayed of characters. So I did a SO and google search that I should change the Collate and Character set of my database. I run this sql
ALTER DATABASE learncon_pywithyou CHARACTER SET utf8 COLLATE utf8_unicode_ci;
from python27 manage.py dbshell, which initiated a mysql shell, what shows on screen is
Query OK, 1 row affected (0.00 sec).
So I assume the problem is solved, but it is not actually. This sql has not done anything, as I later find it in phpMyAdmin provided by Bluehost. All the Varchar fields of all the tables are still in lantin1_swedish_ci collate.
So assume that alter table should work instead. I run this on mysql
alter table mytable character set utf8 collate utf8_unicode_ci;
although on screen it shows Query OK. 4 rows affected, it actually did nothing either, the collate of those fields in mytable did not change at all.
So I finally manually change the fields in phpMyAdmin for mytable and this works, now I am able to insert in this table with unicode and also they display correctly, but I have around 20 tables of such, I don't want to change them one by one manually.
Do we at all have a simple and effective way of changing Collate of each field to store and display correct unicodes?
Changing collation at the database level sets the default for new objects - existing collations will not be changed.
Similarly, at a table level, only new columns (See comment at the bottom) are affected with this:
alter table mytable character set utf8 collate utf8_unicode_ci;
However, to convert the collation of existing columns, you need to add convert to:
alter table mytable convert to character set utf8 collate utf8_unicode_ci;
In addition to #StuartLC ,
For Changing All 20 tables charset and collation use below query, Here world is database name
SELECT
CONCAT("ALTER TABLE ",TABLE_SCHEMA , ".",TABLE_NAME," CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci") AS AlterSQL
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = "world";
The above will prepare all ALTER queries which you need to run.
I'm using PHPMyAdmin and I try to add the NOT NULL constraint to a column of my table.
PHPMyAdmin accepts my following query :
ALTER TABLE `wall` MODIFY `token_message` varchar(40) NOT NULL;
But I can still insert empty strings (=NULL), I don't understand why.
PS : If you're going to give me some other queries to add this constraint, note I've have tried these 3 which don't work in my PHPMyAdmin (kind of error : #1064 - You have an error in your SQL syntax; check the manual) :
ALTER TABLE `wall` ALTER COLUMN `token_message` SET NOT NULL;
ALTER TABLE `wall` ALTER COLUMN `token_message` varchar(40) NOT NULL;
ALTER TABLE `wall` MODIFY `token_message` CONSTRAINTS token_message_not_null NOT NULL;
You wrote, "I can still insert empty strings (=NULL)," which sounds like a misunderstanding. In SQL, an empty string does not evaluate to NULL, or vice versa. Try inserting an empty string and doing SELECT from wall where token_message is NULL. You should get zero rows back. Then try doing an insert where you specify NULL (unquoted) as the value for your column, and you should get the expected error message.
If those tests work as expected, then everything is fine, and your problem is actually that you want to prevent blank strings from being inserted. Check out this question for suggestions, or just check for blank strings during validation, before the query.
MySQL's column alter syntax requires you to completely re-specify the column. You can't just change one attribute of a column, you have to re-define it completely:
ALTER TABLE wall MODIFY token_message varchar(40) NOT NULL default ''
The only 'SET' version allowed is to change the default value.
ref: http://dev.mysql.com/doc/refman/5.1/en/alter-table.html
I think this is a matter of scrubbing your inputs. As octern mentioned, an empty string ('') is not a NULL value in sql. The best way to handle this is to only allow updates through a store procedure which strips out empty strings, even space characters:
CREATE PROC InsertIntoMyDb (#MyVarChar VARCHAR(2000)) AS
SET #MyVarChar = NULLIF(RTRIM(LTRIM(#MyVarChar)), '')
INSERT INTO [TBL] (MyVarChar)
VALUES #MyVarChar
This will truncate any number of spaces to an empty string, turn an empty string into a NULL, and then it will not allow the NULL value to be inserted based on the constraint you already have in place.
Try to use this query
Alter table table_name
change column_name column_name datatype(length) definition
ie,
Alter table wall
change tocken_message tocken_message varchar(40) NOT NULL DEFAULT
I am willing to create a view on a table with a longtext column. But I would like that in my view this column be varchar(255). And Yes I would like to cut the "extra" text.
When I do a substr in the create script the data type is still longtext
Anyone could help me ?
Thanks
How about casting the longtext as a varchar?
CREATE VIEW foo AS
SELECT ID, CAST(MyLongText as char(255)) AS MyVarchar
FROM Table