Technology . Business . Life

I faced problem uploading a huge sql file to my shared hosting server. The size was not that big. It was only 1.8MB in size with about 30,000 records but phpMyAdmin (provided in cpanel) still failed to fully upload and run the file.

I then googled for a solution.

One of the solutions suggest to use SSH but I’m not familiar with it.

Another solution is by using mysqldumper but the configuration seems quite tedious.

Then I found another solution called BigDump which is very straight forward. You upload a PHP script together with your huge sql file via FTP. Then just run the PHP script as usual. In a second all the data has been restored in your database.

You will need this SQL statement to list all duplicate contents in a table

SELECT email,
COUNT(email) AS NumOccurrences
FROM users
GROUP BY email
HAVING ( COUNT(email) > 1 )

source

Sometimes when you are going to execute an SQL statement to your production database, you need to be very careful especially when you are using DELETE or UPDATE command.

To ensure your original data will be available, you can backup the whole table that you are going to do the operation.

To backup the whole table is very easy in phpMyAdmin (even in other SQL tool).

After you done with the operation and it is successful, you can easily drop the temporary backup table.

This is how to do daily mysql backup with cron job in cpanel. This cron job will backup your mysql database as dump file (and gzip) daily. The files will be replaced on the same day next week.

Command to run to dump your mysql database, gzip it and replace it the following week as follow

1

mysqldump -uDBUSERNAME -pPASSWORD --opt DBNAME > /home/USER/dbbackup/FILENAME.sql; gzip -f /home/USER/dbbackup/FILENAME.sql

Replace DBUSERNAME, PASSWORD, DBNAME, USER, FILENAME respectively.

Sometimes you may need to populate a table (usually a temporary or new table) from data of another table (usually huge table).

Here’s is the statement that you may use

INSERT INTO “table1″ (”column1″, “column2″, …)

SELECT “column3″, “column4″, …FROM “table2″

source

I got this error message in my application

Error with database: Table ‘table_name’ is marked as crashed and should be repaired

Went to the net and look for the solution. The simplest one is to click on the “Repair Database” button provided in cpanel

If you want to update multiple records, usually you will have to do a loop and generate multiple SQL statement like this

UPDATE table_name SET fieldname = value1 WHERE fieldname = field_id1;
UPDATE table_name SET fieldname = value2 WHERE fieldname = field_id2;
UPDATE table_name SET fieldname = value3 WHERE fieldname = field_id3;

But to save some resource (perhaps), you can also update multiple records in just one single MySQL statement

UPDATE table_name
SET fieldname = CASE value_id
WHEN value_id1 THEN ‘value1′
WHEN value_id2 THEN ‘value2′
WHEN value_id3 THEN ‘value3′
END
WHERE value_id IN (value_id1,value_id2,value_id3)

I’ve been doing data cleansing of one of my project. Then there was a need to find some abbreviation to be replaced by the real words.

Here I did with mysql statement.

update property set town = replace(town,’tmn’,'taman’)

In general:

update TABLENAME set FIELDNAME = replace (FIELDNAME, searchstr, replacestr)