array in table

[Anon]

Hi,

i have an array with names (John, Marge e.g.) and want to write these names into a table. But I´ve got to check if the names are allready in the table. Can somebody help me ???
I can read the array, but checking my table is difficult to me.

[frymaster]

this is untested. the deal is to go through each name in the array, select
everything from the table where the field name is equal to the name you have
from your array. if the number of rows pulled isn't zero, the name is already
there. if it is zero, the name is not in the db, so you do the insert....

pg_connect("", "", "", "", databasename);

while(list($key, $value) = each($name_array))
{
$result = pg_exec($db, "select * from tbl_foo where name='$value');

if(pg_numrows($result) == 0)
	@pg_exec($db, "insert into tbl_foo (name) values ('$value')");

}

[[deleted]]

You can also let the database do the work.
If you don't want to have any duplicate names in the table,
change your table setup so that the "name" field becomes "unique".
Then just go through the array and insert all names
as they appear. Whenever there is a duplicate, the database will refuse to insert the record and send a nice error to PHP to inform you of this.

Another way would be read all the current names from the table like Frymaster said.
But, read them into an array. Then use array_diff() to find out which names are in your first array, but not in the array you got from the database.
Then insert those names into the database.

[frymaster]

setting a column to unique may not be the best idea, since there may be times when you want to have a non-unique value there. constraints can be very important (esp. if other people are writing code for your database) but can cause problems too.

the array_diff() idea is pretty good. i'm gonna jot that down on the back of an envelope.

[[deleted]]

In this case the whole point of the code seemed to be to prevent the code from entering duplicate names into the database, so a unique contraint seemed to do that pretty well.

But indeed, that does mean that it becomes entirely impossible to ever get duplicates in there, even if you do want to have duplicates.

[Anon]

Thanx,

that was what really works. Thank you

greetings smudl