After creating your table, you need to populate it. The
LOAD DATA
and
INSERT
statements are useful for
this.
Suppose that your pet records can be described as shown here.
(Observe that MySQL expects dates in
'YYYY-MM-DD'
format; this may be different
from what you are used to.)
name | owner | species | sex | birth | death |
---|---|---|---|---|---|
Fluffy | Harold | cat | f | 1993-02-04 | |
Claws | Gwen | cat | m | 1994-03-17 | |
Buffy | Harold | dog | f | 1989-05-13 | |
Fang | Benny | dog | m | 1990-08-27 | |
Bowser | Diane | dog | m | 1979-08-31 | 1995-07-29 |
Chirpy | Gwen | bird | f | 1998-09-11 | |
Whistler | Gwen | bird | 1997-12-09 | ||
Slim | Benny | snake | m | 1996-04-29 |
Because you are beginning with an empty table, an easy way to populate it is to create a text file containing a row for each of your animals, then load the contents of the file into the table with a single statement.
You could create a text file pet.txt
containing one record per line, with values separated by tabs,
and given in the order in which the columns were listed in the
CREATE TABLE
statement. For
missing values (such as unknown sexes or death dates for animals
that are still living), you can use NULL
values. To represent these in your text file, use
\N
(backslash, capital-N). For example, the
record for Whistler the bird would look like this (where the
whitespace between values is a single tab character):
Whistler Gwen bird \N 1997-12-09 \N
To load the text file pet.txt
into the
pet
table, use this statement:
mysql> LOAD DATA LOCAL INFILE '/path/pet.txt' INTO TABLE pet;
If you created the file on Windows with an editor that uses
\r\n
as a line terminator, you should use
this statement instead:
mysql> LOAD DATA LOCAL INFILE '/path/pet.txt' INTO TABLE pet
LINES TERMINATED BY '\r\n';
(On an Apple machine running OS X, you would likely want to use
LINES TERMINATED BY '\r'
.)
You can specify the column value separator and end of line
marker explicitly in the LOAD
DATA
statement if you wish, but the defaults are tab
and linefeed. These are sufficient for the statement to read the
file pet.txt
properly.
If the statement fails, it is likely that your MySQL installation does not have local file capability enabled by default. See Section 6.1.6, “Security Issues with LOAD DATA LOCAL”, for information on how to change this.
When you want to add new records one at a time, the
INSERT
statement is useful. In
its simplest form, you supply values for each column, in the
order in which the columns were listed in the
CREATE TABLE
statement. Suppose
that Diane gets a new hamster named “Puffball.” You
could add a new record using an
INSERT
statement like this:
mysql> INSERT INTO pet
VALUES ('Puffball','Diane','hamster','f','1999-03-30',NULL);
String and date values are specified as quoted strings here.
Also, with INSERT
, you can insert
NULL
directly to represent a missing value.
You do not use \N
like you do with
LOAD DATA
.
From this example, you should be able to see that there would be
a lot more typing involved to load your records initially using
several INSERT
statements rather
than a single LOAD DATA
statement.
Also when you are creating file with null date value (\N) then system showing as 0000-00-00 but when you use NULL for insert command system creating NULL value instead of 0000-00-00. then dba will have extra work to analyze null data isnt it?
Thank you
Burak
OS: WinXP
MySQL: 5.5.8 (included in WAMP server distibution)
INFILE: Made in Notepad, Win XP
Catch was pet.txt file, had to use TAB spacer between, even at last row... Then it still made some NULL rows, so i have positioned my mouse cursor at last row (Slim), behind last NULL word, pressed TAB once, then pressing DELETE so i can knock off those empty spaces..
etc: Fluffy Harold cat f 1993-02-04 \N
Claws Gwen cat m 1994-03-17 \N
Buffy Harold dog f 1989-05-13 \N
Fang Benny dog m 1990-08-27 \N
Bowser Diane dog m 1979-08-31 1995-07-29
Chirpy Gwen bird f 1998-09-11 \N
Whistler Gwen bird \N 1997-12-09 \N
Slim Benny snake m 1996-04-29 \N
It worked, and finally no more NULL rows.
Second, my Load line was:
LOAD DATA LOCAL INFILE 'c:/MySQL/pet.txt' INTO TABLE pet;
No TERMINATION line..
Cheers!
Attempting to load data local infile from the client as stated in the tutorial will result in the following error : ERROR 1148: The used command is not allowed with this MySQL version.
In order to use load data local infile as in the tutorial, use the load-infile option when invoking the client.
From command line, run your client with the load-infile option set to true in order to be able to use load data local infile as in tutorial:
%> mysql --local-infile=1 -p
The instructions for loading data from a local file from the command line work as stated: ie from the shell prompt where the pwd contains the file cr_event_tbl.sql--
%> mysql menagerie < cr_event_tbl.sql
will still work.
Here is the correct syntax for a flat.txt file that is already on the mysql server in a /path/file.txt and you are ssh'd into the box from say a laptop or other networked computer.
mysql> load data infile '/path/to/file/pet.txt' into table pet fields terminated by ',';
Query OK, 76 rows affected, 17 warnings (0.00 sec)
Records: 76 Deleted: 0 Skipped: 0 Warnings: 17
*** terminated by is a good option, and there was no need to specify a '\N'.
*** also if you made the mistake of having leading ',' like I did, you can issue a truncate table foo ; to simply remove current table data, and LOAD DATA INFILE again.
oly562 aka BBT
I have this output:
I just wanted to change all records with DEATH value of '0000-00-00' to NULL, i did the following commands:
mysql> UPDATE pet
-> SET death=NULL
-> WHERE death='0000-00-00'
-> ;
now it displays:
is there a better way? the '0000-00-00' came from an imported CSV which I created using Google Spreadsheet. How come it didn't import as NULL off the bat (except the last record)? NULL and '0000-00-00' were from cells with blank data.
Is '0000-00-00' equals to NULL in a DATE field?
thanks,
Marlon
Fluffy -Tab Space- Harold -Tab Space- cat -Tab Space- f -Tab Space- 1993-02-04 -Tab Space- \N -Tab Space-
This is the way it should look once you load the file with this format:
mysql> SELECT * FROM pet;
9 rows in set (0.00 sec)
I hope this helps.