I have a text file to be imported in a MySQL table. The columns of the files are comma delimited. I set up an appropriate table and I used the command:
load data LOCAL INFILE 'myfile.txt' into table mytable FIELDS TERMINATED BY ‘,’;
The problem is, there are several spaces in the text file, before and after the data on each column, and it seems that the spaces are all imported in the tables (and that is not what I want). Is there a way to load the file without the empty spaces (other than processing each row of the text file before importing in MySQL)?
As far as I understand, there's no way to do this during the actual load of the data file dynamically (I've looked, as well).
It seems the best way to handle this is to either use the SET clause with the TRIM
function
("SET column2 = TRIM(column2)")
or run an update on the string columns after loading, using the TRIM() function.
You can also create a stored procedure using prepared statements to run the TRIM function on all columns in a specified table, immediately after loading it.
You would essentially pass in the table name as a variable, and the sp would use the information_schema database to determine which columns to upload.
If you can use .NET, CSVReader is a great option(http://www.codeproject.com/KB/database/CsvReader.aspx). You can read data from a CSV and specify delimiter, trimming options, etc. In your case, you could choose to trim left and right spaces from each value. You can then either save the result to a new text file and import it into the database, or loop through the CsvReader object and insert each row into the database directly. The performance of CsvReader is impressive. Hope this helps.
Related
I have a database of entries consisting of a 'name', 'id' and a 'description', but currently the 'description' field is set to the file path of a .txt file that actually contains the description content. Each .txt file's name is each row's 'id', plus the .txt extension and they all reside in the same directory.
Can I load and replace each 'description' field with the content from the relevant text file (using MySQL)?
You can't write a MySQL query directly that will read the description values from your file system. That would require the MySQL server to be able to read raw text from files in your file system. You Can't Do That™.
You certainly can write a program in your favorite host language (php, java, PERL, you name it) to read the rows from your database, and update your description rows.
You could maybe contrive to issue a LOAD DATA INFILE command to read each text file. But the text files would have to be very carefully formatted to resemble CSV or TSV files.
Purely using mysql this would be a difficult, if not impossible exercise because mysql does not really offer any means to open files.
The only way to open an external text file from mysql is to use LOAD DATA INFILE command, which imports the text file into a mysql table. What you can do is to write a stored procedure in mysql that:
Create a temporary table with a description field large enough to accommodate all descriptions.
Reads all id and description field contents into a cursor from your base table.
Loop through the cursor and use load data infile to load the given text file's data into your temporary table. This is where things can go wrong. The account under which mysql daemon / service runs needs to have access to the directories and fiels where the description files are stored. You also need to be able to parametrise the load data infile command to read the full contents of the text file into a single field, so you need to set the field and line terminated by parameters to such values that cannot be found in any of the description files. But, even for this you need to use a native UDF (user defined function) that can execute command line programs because running load data infile directly from stored procedures is not allowed.
See Using LOAD DATA INFILE with Stored Procedure Workaround-MySQL for full description how to this.
Issue an update statement using the id from the cursor to update the description field in your base table from the temporary table.
Delete the record from your temp table.
Go to 3.
It may be a lot easier to achieve this from an external programming language, that has better file manipulation functions and can update each record in your base table accordingly.
I'm using Informix LOAD FROM command to bulk insert data from CSV files to a DB table, like:
LOAD FROM "file.csv" DELIMITER ";" INSERT INTO table_name(col1, col2, col3)
The problem is, the first line of each CSV file contains column headers. Is there any way to tell Informix that the first row shall be ignored?
No; there isn't a way to tell standard Informix LOAD statement to skip a header line. Note, too, that it won't remove quotes from around fields in CSV format and otherwise deal with things the way CSV format officially expects (though, since you have semicolon-separated values rather than comma-separated values, it is hard to know which rules are being followed — be leery of the treatment of backslashes too).
You might be able to use the Informix DB-Load utility (dbload) instead; it depends on whether your data is simply using ; in place of Informix's default | delimiter, or whether you have more of the semantics of CSV such as quotes around fields that need to be removed. If you want to get exotic, the Informix High-Performance Loader (HPL) can either handle it natively or be trained to handle it.
Alternatively, you could consider using my* SQLCMD program (it has been called sqlcmd a lot longer than Microsoft's johnny-come-lately of the same name) which allows you to specify:
LOAD FROM "file.csv" DELIMITER ";" SKIP 1 INSERT INTO table_name(col1, col2, col3);
SQLCMD also has an option FORMAT CSV (amongst other formats) that might, or might not, be relevant. It handles things like stripping quotes from around fields that the full CSV standard supports.
You'll need to have Informix ClientSDK and a C compiler (and the rest of a C development system) installed to build SQLCMD.
* Since SQLCMD is my program because I wrote it, any recommendation to use it is inherently biassed; you were warned.
You could also consider an 'external table' (CREATE EXTERNAL TABLE), but I'm not sure it is any better than the LOAD statement either with the formats it supports or with the ability to skip the first row of data.
When I Load CSV files using LOAD FROM into Informix I usually load to a temporary table which is all character columns which I then work with. You just delete the header row. Basically your just putting the whole file into a temp table which is easier to work with.
I hava text file full of values like this:
The first line is a list of column names like this:
col_name_1, col_name_2, col_name_3 ......(600 columns)
and all the following columns have values like this:
1101,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,1101,1,3.86,65,0.46418,65,0.57151...
What is the best way to import this into mysql?
Specifically how to come up with the proper CREATE TABLE command so that the data will load itself properly? What is the best generic data type which would take in all the above values like 1101 or 3.86 or 0.57151. I am not worried about the table being inefficient in terms of storage as I need this for a one time usage.
I have tried some of the suggestions in other related questions like using Phpmyadmin (it crashes I am guessing due to the large amount of data)
Please help!
Data in CSV files is not normalized; those 600 columns may be spread across a couple of related tables. This is the recommended way of treating those data. You can then use fgetcsv() to read CSV files line-by-line in PHP.
To make MySQL process the CSV, you can create a 600 column table (I think) and issue a LOAD DATA LOCAL INFILE statement (or perhaps use mysqlimport, not sure about that).
The most generic data type would have to be VARCHAR or TEXT for bigger values, but of course you would lose semantics when used on numbers, dates, etc.
I noticed that you included the phpmyadmin tag.
PHPMyAdmin can handle this out of box. It will decide "magically" which types to make each column, and will CREATE the table for you, as well as INSERT all the data. There is no need to worry about LOAD DATA FROM INFILE, though that method can be more safe if you want to know exactly what's going on without relying on PHPMyAdmin's magic tooling.
Try convertcsvtomysql, just upload your csv file and then you can download and/or copy the mysql statement to create the table and insert rows.
I have some small data with slashes in it.
I am doing a csv import with over 2000 lines. I am looping through each one and it goes fine but when I have slashes in the text the whole string wont import. I dont get any errors. The data just doesn't show up in the database.
Sample text would be "Barr/Massive"
How can I make it so mysql doesn't strip the slash.
Use bind parameters, don't insert the data directly into your SQL.
INSERT INTO table VALUES ($name)
versus
INSERT INTO table VALUES (?)
I'm assuming you're using some kind of PHP or Perl script for this. Otherwise, phpMyAdmin has a CSV import.
As the title says: I've got a bunch of tab-separated text files containing data.
I know that if I use 'CREATE TABLE' statements to set up all the tables manually, I can then import them into the waiting tables, using 'load data' or 'mysqlimport'.
But is there any way in MySQL to create tables automatically based on the tab files? Seems like there ought to be. (I know that MySQL might have to guess the data type of each column, but you could specify that in the first row of the tab files.)
No, there isn't. You need to CREATE a TABLE first in any case.
Automatically creating tables and guessing field types is not part of the DBMS's job. That is a task best left to an external tool or application (That then creates the necessary CREATE statements).
If your willing to type the data types in the first row, why not type a proper CREATE TABLE statement.
Then you can export the excel data as a txt file and use
LOAD DATA INFILE 'path/file.txt' INTO TABLE your_table;