Home > Article > Backend Development > How to call three databases with PHP (2)_PHP tutorial
Open Database Connectivity (ODBC) has become an industry standard for communicating with databases. PHP also provides a standard interface, allowing PHP to call Access, SQL SERVER and other databases. The related functions are:
(1) integer odbc_connect(string dsn, string user, string password)
Connect to an ODBC database source name.
(2) integer odbc_exec(integer connection, string query) or odbc_do(integer connection, string query)
Execute a query on a connection.
(3) boolean odbc_fetch_row(integer result, integer row)
Get a row of data from a result set. The Row parameter is optional. If left blank, the next valid row is returned. Returns false when there are no more rows remaining in the result set.
(4) boolean odbc_close(integer connection)
Close a database connection. If there is an open transaction on the connection, an error is returned and the connection is not closed.
Finally, let’s look at an example of paging:
//Set the number of items displayed on each page
$show_num = 10;
$spages = $pages;//Avoid $pages being changed later
//Define the connection
$dsn = "localhost";
$ user = "sa";
$password = "";
//Calculate the total number of records
$rs_num = "select count(*) as id from bbs where zu='0' and lei='".$lei."'";
$conn_id = odbc_connect($dsn,$user,$password);
$rnum = odbc_exec( $conn_id,$rs_num);
while(odbc_fetch_row($rnum)){
$total_rs = odbc_result($rnum,"id");//Put the total number of records into $ total_rs variable
}
//Calculate the number of items related to the page
$nnn = $total_rs / $show_num;//Calculate the total number of pages
$hnnn = intval($nnn);//Round the total number of pages
$cnnnn = $nnn - $hnnn;
//Calculate the total number of pages required
switch ($cnnn){
case "0":
$hnnn++;
$nnn = $hnnn;//Total number of pages
break;
default:
$nnn = $hnnn;//Total number of pages
break;
};
if ($nnn == 0)$nnn++;
//Calculate the conditions required for page changes
$fore = $pages;
$next = $pages ;
$fore -= 1;
$next += 1;
if ($fore > 0) {
echo "< a>Homepage";
echo "Previous page";
};
if ($pages < ; $nnn) {
echo "Next page";
echo "Last page";
};
echo "total".$nnn."pages";
$query_string = "SELECT * FROM table where condition order by you wanted order";
$cur = odbc_exec($conn_id,$query_string);
//Get to the top of the loop
$cnum = ($pages-1) * $show_num;//Calculate the current The position of the record cursor
//Empty loop to display the record cursor
if ($cnum != 0){
for ($i=0;$i< ;=$cnum;odbc_fetch_row($cur)){$i++;};
};
$i=1;
//Display record
while(odbc_fetch_row($cur)){
echo ;
if ($i == $show_num){//Jump out of the program when the number of pages is not satisfied
break;
};
$i++;
};
//Close the connection
odbc_close($conn_id);
?>