PostgreSQL: load a file from filesystem without inserting into a table - mysql

How do I do such a thing?
In mysql I do:
SELECT LOAD_FILE('/path/to/file');
What about postgres? Without using the \copy command of psql?

That depends what you want to do exactly.
You have COPY for reading structured data into (temporary) tables.
Note that this is the SQL command, which is similar, but not the same as the \copy command of psql!
And there is pg_read_file() for reading in any text file.
Edit - a basic example:
CREATE FUNCTION f_showfile(myfile text)
RETURNS text AS
$x$
BEGIN
RETURN pg_read_file(myfile, 0, 1000000); -- 1 MB max.
-- or you could read into a text var and do stuff with it.
END;
$x$
LANGUAGE plpgsql VOLATILE;
Only superusers can use this function. Be careful not to open security holes. You could create a function with SECURITY DEFINER, REVOKE FROMpublic and GRANT TO selected roles. If security is an issue read this paragraph at the provided link:
Writing SECURITY DEFINER Functions Safely
pg_read_file() you can only read from the logfile dir and the database dir. On Linux you could create a symlink to a data dir (at a safe location) like this:
cd /path//my/database
ln -s /var/lib/postgresql/text_dir/ .
Then call like this:
SELECT f_showfile('text_dir/readme.txt');
Output:
f_showfile
-------------------------------------------------------------------------
This is my text from a file.

Related

automate csv import in mysql db in linux environment

Is there a way to have a .csv imported into a SQL Table automatically in mysql db? I know how to do it manually, but there is a situation where a .csv is exported nightly from PeopleSoft and we want that imported automatically into SQL Table in linux environment. plese give me a sample script to do that.. If there's a way, can anyone point me in that direction (I'm not a SQL expert)!!
You can try creating Stored procedure,
Write load csv query into SP.
Create Event to call SP.
I hope this helps.
CREATE EVENT IF NOT EXISTS `load_csv_event`
ON SCHEDULE EVERY 23 DAY_HOUR
DO CALL my_sp_load_csv();
Alos, You can directly create an event and write a load query into it.
You could create a crontab job, for example:
* * * * * /path/to/load_script.sh
Where load_script.sh may be like (do not forget make it executable):
#!/bin/bash
IMPORTED_FILE_PATH=/path/to/your/imported/file.csv
TABLENAME=target_table_name
DATABASE=db_name
TMP_FILENAME=/tmp/${TABLENAME}.cvs
# do nothing if imported file does not exist
[ -f "$IMPORTED_FILE_PATH" ] || exit 0
# if temporary file exists, then it means previous import job is running. Also do nothing
[ -f "$TMP_FILENAME" ] && exit 0
# Move it to tmp and rename to target table name
mv "$IMPORTED_FILE_PATH" "$TMP_FILENAME"
mysqlimport --user=mysqlusername --password=mysqlpassword --host=mysqlhost --local $DATABASE $TMP_FILENAME
rm -f "$TMP_FILENAME"
It is just an example (not tested). You should add error handling, logging, etc.
Also look at manual of mysqlimport

Running mySQL queries from a script

For my database class the teacher assigned us to use Oracle SQL to design an application. Because I have more experience with mySQL he said I could use it instead.
I want to make my assignment look as simliar to his example as possible. What his example consists of of is one file run.sql that looks like this:
#start //this runs start.sql which creates the tables
DESC table_name; //do this for all tables
#insert //this runs insert.sql that creates dummy data
SELECT * FROM table_name; //do this for all tables
#query //this runs query.sql that runs our sample queries
#drop //this kills all the data
Is there a way to do something simliar?
Namely a way to write a query that calls external queries and outputs all data to an output.txt file?
Use 'source' to input the *.sql files
use 'create procedure' to generate the 'drop' function
use "into outfile '/file/path';" on your select to write out.
double redirect to append: "into outfile '>>/file/path';"
The source command for the mysql command-line client could do the job here:
source start.sql;
DESC table_name;
You can get more commands with help.

Using mysqldump to format one insert per line?

This has been asked a few times but I cannot find a resolution to my problem. Basically when using mysqldump, which is the built in tool for the MySQL Workbench administration tool, when I dump a database using extended inserts, I get massive long lines of data. I understand why it does this, as it speeds inserts by inserting the data as one command (especially on InnoDB), but the formatting makes it REALLY difficult to actually look at the data in a dump file, or compare two files with a diff tool if you are storing them in version control etc. In my case I am storing them in version control as we use the dump files to keep track of our integration test database.
Now I know I can turn off extended inserts, so I will get one insert per line, which works, but any time you do a restore with the dump file it will be slower.
My core problem is that in the OLD tool we used to use (MySQL Administrator) when I dump a file, it does basically the same thing but it FORMATS that INSERT statement to put one insert per line, while still doing bulk inserts. So instead of this:
INSERT INTO `coupon_gv_customer` (`customer_id`,`amount`) VALUES (887,'0.0000'),191607,'1.0300');
you get this:
INSERT INTO `coupon_gv_customer` (`customer_id`,`amount`) VALUES
(887,'0.0000'),
(191607,'1.0300');
No matter what options I try, there does not seem to be any way of being able to get a dump like this, which is really the best of both worlds. Yes, it take a little more space, but in situations where you need a human to read the files, it makes it MUCH more useful.
Am I missing something and there is a way to do this with MySQLDump, or have we all gone backwards and this feature in the old (now deprecated) MySQL Administrator tool is no longer available?
Try use the following option:
--skip-extended-insert
It worked for me.
With the default mysqldump format, each record dumped will generate an individual INSERT command in the dump file (i.e., the sql file), each on its own line. This is perfect for source control (e.g., svn, git, etc.) as it makes the diff and delta resolution much finer, and ultimately results in a more efficient source control process. However, for significantly sized tables, executing all those INSERT queries can potentially make restoration from the sql file prohibitively slow.
Using the --extended-insert option fixes the multiple INSERT problem by wrapping all the records into a single INSERT command on a single line in the dumped sql file. However, the source control process becomes very inefficient. The entire table contents is represented on a single line in the sql file, and if a single character changes anywhere in that table, source control will flag the entire line (i.e., the entire table) as the delta between versions. And, for large tables, this negates many of the benefits of using a formal source control system.
So ideally, for efficient database restoration, in the sql file, we want each table to be represented by a single INSERT. For an efficient source control process, in the sql file, we want each record in that INSERT command to reside on its own line.
My solution to this is the following back-up script:
#!/bin/bash
cd my_git_directory/
ARGS="--host=myhostname --user=myusername --password=mypassword --opt --skip-dump-date"
/usr/bin/mysqldump $ARGS --database mydatabase | sed 's$VALUES ($VALUES\n($g' | sed 's$),($),\n($g' > mydatabase.sql
git fetch origin master
git merge origin/master
git add mydatabase.sql
git commit -m "Daily backup."
git push origin master
The result is a sql file INSERT command format that looks like:
INSERT INTO `mytable` VALUES
(r1c1value, r1c2value, r1c3value),
(r2c1value, r2c2value, r2c3value),
(r3c1value, r3c2value, r3c3value);
Some notes:
password on the command line ... I know, not secure, different discussion.
--opt: Among other things, turns on the --extended-insert option (i.e., one INSERT per table).
--skip-dump-date: mysqldump normally puts a date/time stamp in the sql file when created. This can become annoying in source control when the only delta between versions is that date/time stamp. The OS and source control system will date/time stamp the file and version. Its not really needed in the sql file.
The git commands are not central to the fundamental question (formatting the sql file), but shows how I get my sql file back into source control, something similar can be done with svn. When combining this sql file format with your source control of choice, you will find that when your users update their working copies, they only need to move the deltas (i.e., changed records) across the internet, and they can take advantage of diff utilities to easily see what records in the database have changed.
If you're dumping a database that resides on a remote server, if possible, run this script on that server to avoid pushing the entire contents of the database across the network with each dump.
If possible, establish a working source control repository for your sql files on the same server you are running this script from; check them into the repository from there. This will also help prevent having to push the entire database across the network with every dump.
As others have said using sed to replace "),(" is not safe as this can appear as content in the database.
There is a way to do this however:
if your database name is my_database then run the following:
$ mysqldump -u my_db_user -p -h 127.0.0.1 --skip-extended-insert my_database > my_database.sql
$ sed ':a;N;$!ba;s/)\;\nINSERT INTO `[A-Za-z0-9$_]*` VALUES /),\n/g' my_database.sql > my_database2.sql
you can also use "sed -i" to replace in-line.
Here is what this code is doing:
--skip-extended-insert will create one INSERT INTO for every row you have.
Now we use sed to clean up the data. Note that regular search/replace with sed applies for single line so we cannot detect the "\n" character as sed works one line at a time. That is why we put ":a;N;$!ba;" which basically tells sed to search multi-line and buffer the next line.
Hope this helps
What about storing the dump into a CSV file with mysqldump, using the --tab option like this?
mysqldump --tab=/path/to/serverlocaldir --single-transaction <database> table_a
This produces two files:
table_a.sql that contains only the table create statement; and
table_a.txt that contains tab-separated data.
RESTORING
You can restore your table via LOAD DATA:
LOAD DATA INFILE '/path/to/serverlocaldir/table_a.txt'
INTO TABLE table_a FIELDS TERMINATED BY '\t' ...
LOAD DATA is usually 20 times faster than using INSERT statements.
If you have to restore your data into another table (e.g. for review or testing purposes) you can create a "mirror" table:
CREATE TABLE table_for_test LIKE table_a;
Then load the CSV into the new table:
LOAD DATA INFILE '/path/to/serverlocaldir/table_a.txt'
INTO TABLE table_for_test FIELDS TERMINATED BY '\t' ...
COMPARE
A CSV file is simplest for diffs or for looking inside, or for non-SQL technical users who can use common tools like Excel, Access or command line (diff, comm, etc...)
I'm afraid this won't be possible. In the old MySQL Administrator I wrote the code for dumping db objects which was completely independent of the mysqldump tool and hence offered a number of additional options (like this formatting or progress feedback). In MySQL Workbench it was decided to use the mysqldump tool instead which, besides being a step backwards in some regards and producing version problems, has the advantage to stay always up-to-date with the server.
So the short answer is: formatting is currently not possible with mysqldump.
Try this:
mysqldump -c -t --add-drop-table=FALSE --skip-extended-insert -uroot -p<Password> databaseName tableName >c:\path\nameDumpFile.sql
I found this tool very helpful for dealing with extended inserts: http://blog.lavoie.sl/2014/06/split-mysqldump-extended-inserts.html
It parses the mysqldump output and inserts linebreaks after each record, but still using the faster extended inserts. Unlike a sed script, there shouldn't be any risk of breaking lines in the wrong place if the regex happens to match inside a string.
I liked Ace.Di's solution with sed, until I got this error:
sed: Couldn't re-allocate memory
Thus I had to write a small PHP script
mysqldump -u my_db_user -p -h 127.0.0.1 --skip-extended-insert my_database | php mysqlconcatinserts.php > db.sql
The PHP script also generates a new INSERT for each 10.000 rows, again to avoid memory problems.
mysqlconcatinserts.php:
#!/usr/bin/php
<?php
/* assuming a mysqldump using --skip-extended-insert */
$last = '';
$count = 0;
$maxinserts = 10000;
while($l = fgets(STDIN)){
if ( preg_match('/^(INSERT INTO .* VALUES) (.*);/',$l,$s) )
{
if ( $last != $s[1] || $count > $maxinserts )
{
if ( $count > $maxinserts ) // Limit the inserts
echo ";\n";
echo "$s[1] ";
$comma = '';
$last = $s[1];
$count = 0;
}
echo "$comma$s[2]";
$comma = ",\n";
} elseif ( $last != '' ) {
$last = '';
echo ";\n";
}
$count++;
}
add
set autocommit=0;
to first line of your sql script file, then import by:
mysql -u<user> -p<password> --default-character-set=utf8 db_name < <path>\xxx.sql
, it will fast 10x.

MySQL script with parameters

I want to create a deployment script, somehow emulate Oracle deployment scripts, where with &param you can use previously declared parameters.
I need to call this script for different users on different databases automatically.
For example my script should be:
USE &param;
DROP TABLE IF EXISTS `TEST` ;
CREATE TABLE IF NOT EXISTS `TEST` (X INT(16))
etc....
Of course &param is what I would have used in Oracle environment.
Thanks
Updates:
Forgot to mention that I am using a windows environment for now. I have created a batch script to call the mysql script. The easiest way I thought would be to pass to mysql 2 command: 1) use the schema I have as parameter and then call the script which will create the table regardless of the schema. Unfortunately mysql seems to understand that I want to connect to the schema X, but doesn't want to call the script.
REM param is the schema and mainsql is the script
SET param="%1"
SET mainsql="script.sql"
echo %param%
echo %mainsql%
mysql -u <user> --password=<psw> %param% "source %mainsql%;"
As far as I know you can't directly pass variables in to a MySQL script. The best you can do is set user variables in a wrapper shell script. Something like:
passed_var1=$1
passed_var2=$2
mainsql=script.sql
mysql $(usual_parameters) -e "set #user_var1=$passed_var1; set #user_var2=$passed_var2; source $mainsql"
Adjust for actual use, of course.

Using shell script to insert data into remote MYSQL database

I've been trying to get a shell(bash) script to insert a row into a REMOTE database, but I've been having some trouble :(
The script is meant to upload a file to a server, get a URL, HASH, and a file size, connect to a remote mysql database, and insert the data into an existing table. I've gotten it working until the remote MYSQL database bit.
It looks like this:
#!/bin/bash
zxw=randomtext
description=randomtext2
for file in "$#"
do
echo -n *****
ident= *****
data= ****
size=` ****
hash=`****
mysql --host=randomhost --user=randomuser --password=randompass randomdb
insert into table (field1,field2,field3) values('http://www.example.com/$hash','$file','$size');
echo "done"
done
I'm a total noob at programming so yeah :P
Anyway, I added the \ to escape the brackets as I was getting errors. As it is right now, the script is works fine until connects to the mysql database. It just connects to the mysql database and doesn't do the insert command (and I don't even know if the insert command would work in bash).
PS: I've tried both the mysql commands from the command line one by one, and they worked, though I defined the hash/file/size and didn't have the escaping "".
Anyway, what do you guys think? Is what I'm trying to do even possible? If so how?
Any help would be appreciated :)
The insert statement has to be sent to mysql, not another line in the shell script, so you need to make it a "here document".
mysql --host=randomhost --user=randomuser --password=randompass randomdb << EOF
insert into table (field1,field2,field3) values('http://www.site.com/$hash','$file','$size');
EOF
The << EOF means take everything before the next line that contains nothing but EOF (no whitespace at the beginning) as standard input to the program.
This might not be exactly what you are looking for but it is an option.
If you want to bypass the annoyance of actually including your query in the sh script, you can save the query as .sql file (useful sometimes when the query is REALLY big and complicated). This can be done with simple file IO in whatever language you are using.
Then you can simply include in your sh scrip something like:
mysql -u youruser -p yourpass -h remoteHost < query.sql &
This is called batch mode execution. Optionally, you can include the ampersand at the end to ensure that that line of the sh script does not block.
Also if you are concerned about the same data getting entered multiple times and your rdbms getting inconsistent, you should explore MySql transactions (commit, rollback, etc).
Don't use raw SQL from bash; bash has no sane facility for sanitizing the data beforehand. Generate a CSV file and upload that instead.