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After creating your table, you need to populate it. The LOAD DATA
and
INSERT
statements are useful for this.
Suppose 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):
name | owner | species | sex | birth | death |
Whistler | Gwen | bird | \N | 1997-12-09 | \N |
To load the text file `pet.txt' into the pet
table, use this
command:
mysql> LOAD DATA LOCAL INFILE "pet.txt" INTO TABLE pet; |
Note that if you created the file on Windows with an editor that uses
\r\n
as a line terminator, you should use:
mysql> LOAD DATA LOCAL INFILE "pet.txt" INTO TABLE pet -> LINES TERMINATED BY '\r\n'; |
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
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 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); |
Note that 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.
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