db_table_exists(NULL) = number of tables in the db [#107237]

I'm not sure if this is a bug or the intended behaviour :
db_table_exists(NULL) or db_table_exists(empty string) return the number of tables in the database.

Yet you'd expect code like the following would prevent you from errors :

if (db_table_exists($var)) {
  db_query('SELECT FROM {'. $var .'} WHERE ...');
}

Comment	File	Size	Author
#5	db_table_exists_1.patch	2.2 KB	kbahey
#5
#2	db_table_exists_0.patch	1.26 KB	yched
#2

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Comments

Comment #1

yched CreditAttribution: yched commented 6 January 2007 at 03:11

That's with MySQL 4.1, btw

Comment #2

yched CreditAttribution: yched commented 6 January 2007 at 15:57

Status:

Active

» Needs review

File	Size
db_table_exists_0.patch	1.26 KB

Actually I think it's a bug.
It does not match the function description, and I don't think the pgsql equivalent behaves the same (it uses a "WHERE name = $tablename" style construct.

Attached patch checks if the provided name is empty and returns 0. (usual PHP 'empty' stuff : it will also reject '0', which I think is not a valid table name anyway - could be fixed, but I did not want to add too much cruft)

It do not think this is baby sitting broken code either :

if (db_table_exists($var)) {
  // query the $var table being confident that it exists
}

cannot be considered broken code IMO, and should be considered 'the right way'

Comment #3

bdragon CreditAttribution: bdragon commented 6 January 2007 at 17:21

How about this?

return (db_num_rows(db_query("SHOW TABLES LIKE '{" . db_escape_table($table) . "}'")) == 1);

Comment #4

drumm

he/him

NY, US

CreditAttribution: drumm commented 8 April 2007 at 02:20

Version:	5.x-dev	» 6.x-dev
Status:	Needs review	» Needs work

If you want to return FALSE, then return that and not the number 0.

Comment #5

kbahey CreditAttribution: kbahey commented 8 April 2007 at 02:51

Status:

Needs work

» Needs review

File	Size
db_table_exists_1.patch	2.2 KB

Here is a patch to mysql, mysqli, and pgsql.

It checks that $table is indeed passed in, and if so, it executes the query, otherwise it returns FALSE;

Comment #6

keith.smith CreditAttribution: keith.smith commented 24 June 2007 at 01:15

Status:

Needs review

» Needs work

patch no longer applies

# patch -p0 < db_table_exists_1.patch
patching file includes/database.mysqli.inc
Hunk #1 FAILED at 398.
1 out of 1 hunk FAILED -- saving rejects to file includes/database.mysqli.inc.rej
patching file includes/database.mysql.inc
Hunk #1 FAILED at 418.
1 out of 1 hunk FAILED -- saving rejects to file includes/database.mysql.inc.rej
patching file includes/database.pgsql.inc
Hunk #1 FAILED at 391.
1 out of 1 hunk FAILED -- saving rejects to file includes/database.pgsql.inc.rej

Comment #7

dpearcefl CreditAttribution: dpearcefl commented 19 June 2011 at 22:49

Is there any interest or a need for this this be fixed?

Comment #8

2 March 2016 at 22:18

Status:

Needs work

» Closed (outdated)

Automatically closed because Drupal 6 is no longer supported. If the issue verifiably applies to later versions, please reopen with details and update the version.