In this paper, we share two kinds of
How PHP data is accessed, we can compare and analyze the similarities and differences between the two ways, and finally provide a small exercise for everyone, the details are as follows
Way One: obsolete, only do understand
1. Making a connection (establishing a channel)
$db =mysql_connect ("localhost", "root", "123"); In parentheses are "server address", "User name", "Password"
2. Select which database to operate
mysql_select_db ("MyDB", "$db");
3. Write SQL statements
$sql = "SELECT * from Info";
4. Execute SQL statements
$result =mysql_query ($sql); Query has the meaning of inquiry
5. Fetching data from the result set ($result)
$row =mysql_fetch_row ($result); Reads one row of data $row1=mysql_fentch_row ($result) per execution; Executes the second data var_dump ($row);//Read all data with a loop: while ($row =mysql_fetch_row ($result)) {var_dump ($row); }
method Two: Object-oriented
1. Create a Connection object:
$db =new mysqli ("localhost", "root", "123", "mydb")//in parentheses the contents are "server address", "username", "password", "Database name"
2. Determine if the connection is faulty:
2.1 Mysqli_connect_error (); Error on behalf of connection
2.2
if (Mysqli_connect_erroe ())
{
echo "Connection failed!";
Exit (); Exit program
}
2.3!mysqli_connect_error or Die ("Connection failed! "); "or" Before the connection is correct, which means the connection failed
3. Write the SQL statement:
$sql = "SELECT * From Nation";
4. Execute SQL statement: If the execution succeeds in returning the result set object, if the execution fails returns false
$result = $db->query ($sql);
5. Read the data from the result set, first determine if there is any data
if ($result) {//Returns an indexed array of rows of data, each execution returns a data Var_dump ($result->fetch_row ()); while ($row = $result->fetch_row) {var_dump ($row); }//Returns an associative array of rows of data, with each execution returning a data var_dump ($result->fetch_row ()); Returns all data Var_dump ($result->fetch_all ()) through a two-dimensional array; Returns a row of data as an object Var_dump ($result->fetch_object ());}
Practice:
1. The form of the following drop-down menu displays the Nation table on the page
$db =new mysqli ("localhost", "root", "" "," MyDB ");! Mysqli_connection_erroe () or Die ("Connection failed! $sql = "Select*from Nation", $result = $db->query ($sql), if ($result) {$att = $result->fetch_all (); echo ""; foreach ($att as $value) {echo '{$value [1]} "; } echo "";}
2. Find out the Info table and display it in tabular form
$db =new mysqli ("localhost", "root", "" "," MyDB ");! Mysqli_connecton_error () or Die ("Connection failed! $sql = "SELECT * from Info", $result = $bd->query ($sql), if ($result) {$att = $result->fetch_all (); echo "
"; Echo"
Code |
Name |
Gender |
National |
Birthday |
"; foreach ($att as $value) {echo"
{$value [0]} |
{$value [1]} |
{$value [2]} |
{$value [3]} |
{$value [4]} |
";} echo "
";} You can also use the For loop if ($result) {$arr = $result->fetch_all (); echo "
"; echo "
Code |
Name |
Sex |
Nation |
Birthday |
"; for ($i =0; $i
{$arr [$i][0]} |
{$arr [$i][1]} |
{$arr [$i][2]} |
{$arr [$i][3]} |
{$arr [$i][4]} |
"; } echo "
";}</tr>
The above is the whole content of this article, I hope that you learn PHP programming help.