PHP和MySQLi检查表是否存在以及是否不创建表

Question

Attempting to use this to check to see if the table exists and if it doesn't create it

if ( !f_tableExists($table, DB_NAME) ) {
    $sql = "CREATE TABLE $table (
        ID int NOT NULL AUTO_INCREMENT,
        PRIMARY KEY(ID),
        timestamp int NOT NULL,
        ip int NOT NULL
    )";

    $result = mysqli_query($sql);

    if (!$result) {
        die('Invalid query: ' . mysqli_error());
    }

}

where f_tableExists does the following to check if it exists.

function f_tableExists($tablename, $database = false) {

if(!$database) {
    $res = mysqli_query("SELECT DATABASE()");
    $database = mysqli_data_seek($res, 0);
}

$res = mysqli_query("
    SELECT COUNT(*) AS count
    FROM information_schema.tables
    WHERE table_schema = '$database'
    AND table_name = '$tablename'   
");

return mysqli_data_seek($res, 0) == 1;
}

Getting the result 'Invalid query:'

No table is being made and hence I assume some of my mysqli query code (CREATE TABLE....ip int NOT NULL) or (SELECT COUNT...= '$tablename') or another bit is wrong and/or not working? I don't know which bit or why?

Answer 1

Just use query with IF NOT EXISTS without checking

http://dev.mysql.com/doc/refman/5.5/en/create-table.html

  $sql = "CREATE TABLE IF NOT EXISTS $table (
        ID int NOT NULL AUTO_INCREMENT,
        PRIMARY KEY(ID),
        timestamp int NOT NULL,
        ip int NOT NULL
    )";

Also, need pass connection into mysqli_query

PS relative joke: http://www.bash.org/?725783

Answer 2

hey this how you could have done it:

create a mysqli php connection:

<?php
$__DATABASE__='centralfeed_feed';
$__USER__='root';
$__PASSWORD__='';
$__HOST__='localhost';

$con=mysqli_connect($__HOST__,$__USER__,$__PASSWORD__,$__DATABASE__);

?>

then make the mysqli request to database:

<?php

     if(mysqli_query($con,"DESCRIBE  users ")){
        echo "exists";
    }else{
        echo "dont exists";
    }
    mysqli_close($con);
    exit;
 ?>

then your done !!

Always remember to close connection when ever your done using them or note using them connections not just in php mysqli but all the time(in other languages as well).