I'm trying to backup some of my data stored in a big table with
SELECT ... INTO OUTFILE
statement.
The output file is on a network hard drive, so if the network connection breaks just during the dump (it takes one minute more or less) I find a partial file on my network hard drive and I'd like to mark such file as "wrong".
Is there a SQL command that I can give inside my MySQL Stored Procedure that let me rename such file?
Thank you very much
Best
cghersi
You can't rename file in mysql, but you could use two files for dump and rotate it only when operation was successful.
Example:
You make dump to 'a.csv', if operation was successful will use 'b.csv' for next dump, otherwise use 'a.csv' again. And so on...
Related
How can I track the execution of source filename command in mysql so that I can have the filename and path of sql scripts that's been run. Google didn't help or may be I didn't use the right keyword.
So when I execute source ./test/file.sql (without errors preferably)
I want an entry in "source_history" table with current_time,filename(along with path) which I can do if I could figure how to track.
It'd be of great help if anyone could help me in keeping track of the command source.(Something like a trigger event for insert or update on table)
(may be, tracking all command in that sense and then while exiting mysql, get the query history and check for source)
Hope that makes sense.
Thanks in advance.
The problem is that the source command is not a MySQL command, it is a command in MySQL's command line interface, which is also named MySQL.
CLI only passes the sql commands within the file to the MySQL server, therefore the server cannot be aware of the exact file used for executing the command.
MySQL own documentation the source command (see the link above) suggests the most obvious solution:
Sometimes you may want your script to display progress information to
the user. For this you can insert statements like this:
SELECT '<info_to_display>' AS ' ';
So, the simples way is to create a table with fields for path, event type (start / stop) and a timestamp and add insert statements to the start and end of each sql file that log the start and the end of each batch and supply the name of the file hard coded in the insert statements. You may want to create a script that adds these commands to the sql files.
Alternative is to create a batch file that receives a path to an .sql file in a parameter, invokes MySQL's CLI, logs the start of the batch process in mysql, launches the .sql file, and then logs the completion of the batch in MySQL.
I know how to import a text file into MySQL database by using the command
LOAD DATA LOCAL INFILE '/home/admin/Desktop/data.txt' INTO TABLE data
The above command will write the records of the file "data.txt" into the MySQL database table. My question is that I want to erase the records form the .txt file once it is stored in the database.
For Example: If there are 10 records and at current point of time 4 of them have been written into the database table, I require that in the data.txt file these 4 records get erased simultaneously. (In a way the text file acts as a "Queue".) How can I accomplish this? Can a java code be written? Or a scripting language is to be used?
Automating this is not too difficult, but it is also not trivial. You'll need something (a program, a script, ...) that can
Read the records from the original file,
Check if they were inserted, and, if they were not, copy them in another file
Rename or delete the original file, and rename the new file to replace the original one.
There might be better ways of achieving what you want to do, but, that's not something I can comment on without knowing your goal.
I want to run several .sql files in a defined order. So I thought to write a stored procedure which is called for each file in another .sql file.I can't find an example of such a mysql procedure.If you can please help me.
In theory, I think you could use LOAD DATA INFILE to load the files into a temp table, then use a cursor to iterate through the temp table and use PREPARE and EXECUTE to execute each one -- if MySQL allows those commands in a stored procedure -- but that's a really bad way of accomplishing this. Stored procedures should be used for manipulating data in the DB, and LOAD DATA INFILE should be used to load data, not executable statements. If you need to execute SQL that has been saved externally, you should use the intended external methods for doing so.
The reason you're having trouble finding out how to do what you're describing is because there's a much easier way to do what you're trying to accomplish, and what you're trying to do is against philosophy.
You can either create a batch or shell script file like so:
mysql db_name < FirstFile.sql
mysql db_name < SecondFile.sql
.
.
.
Or, you can create a master .sql file that sources the individual commands in order. Say you have a file master.sql with contents like:
source FirstFile.sql
source SecondFile.sql
.
.
.
Then you run mysql db_name < master.sql.
I am trying to upload a 32mb MYSQL database into a pre-existing database, but the php admin on my shared hosting has a 10mb limit... I have tried zipping it up - but when the server unzips the database, the uncompressed file is too large for the server to handle.
Is it possible to split the database up and upload it by pasting it in parts as an SQL query - I assume I would need each chunk to have something at the start of it which says
"Import this data into the pre-existing tables in the database"
What would this be?
At the moment there is a few hundred lines saying things like "CREATE" and "INSERT INTO"
You might try connecting to the database remotely with mysql workbench, or command line tool mysql. If you can do that, you can run:
source c:/path/to/your/file.sql
and you won't be constrained by phpmyadmin's upload size restrictions. Most shared hosting I've seen allows it. If not, you may just need to grant permissions for the user#host in phpmyadmin (or whatever the interface is).
The dump file created by mysqldump is just a set of SQL statements that will rebuild your tables.
To load it in in chunks I'd recommend either dumping it out in sets of tables and loading them one by one or if required the dump file should be roughly in the same (pseudo) format:
Set things up ready for loading
CREATE TABLE t1;
INSERT INTO TABLE t1...;
INSERT INTO TABLE t1...;
CREATE TABLE t2;
INSERT INTO TABLE t2...;
INSERT INTO TABLE t2...;
Finalise stuff after loading
You can manually split the file up by keeping the commands at the start and finish and just choosing blocks for individual tables by looking for their CREATE TABLE statements.
I have a database backup for which SQL Server Management Studio says that it has three files in it: an .mdf file, an .ndf file and one .ldf file. This secondary data file (the .ndf one) was created for no obvious reason, so I want to remove it altogether (without losing data, of course), preferably during while the database is being restored from the backup.
Is this at all doable?
Ok, found a solution.
First back up the database.
Execute this:
USE database_name;
Then execute this, and replace logical_ndf_file_name with the logical name of your NDF file (which you can easily find out via Database->Properties_Files):
DBCC SHRINKFILE('logical_ndf_file_name', EMPTYFILE);
ALTER DATABASE database_name REMOVE FILE logical_ndf_file_name;
I ran the empty followed by ndf drop during produciton load successfully. I think it is important to run the drop ndf in the same transaction as the empty to ensure the database doesn't try to write to the file you are deleting, but then after an empty the database marks the files unusable, evidenced by attempting another empty shorty after.