Data access, accessing data using the MySQL class

Data access is divided into three types

1. Use the function to discard the new version

2. Object-oriented approach Mysqli class

The way of 3.PDO

Example

<table width= "100%" border= "1" >
<tr>
<td> Code </td>
<td> name </td>
<td> Sex </td>
<td> ethnic </td>
<td> Birthdays </td>
</tr>

Use the Mysqli class to access the database:

1. The object in Mysqli, which is equivalent to establishing a channel between PHP and MySQL database

$db = new Mysqli ("localhost", "root", "123", "MyDB");

2. Determine if the connection is wrong

if (Mysqli_connect_error ()) {

echo "Connection failed! ";

Exit If the connection goes wrong, end the program directly

}

3. Write SQL statements

$sql = "SELECT * from Info";

4. Execute the prepared SQL statement

$result = $db->query ($sql);

Returns the result set object if a query statement is executed, or true or false if other statements are executed

5. Reading data from the result set object

$arr 1 = $result->fetch_row (); Read one at a time, return an array

You can use the while loop to read all data

while ($arr = $result->fetch_row ()) {

Var_dump ($arr);

}

$arr = $result->fetch_all (); Read all, return two-dimensional array

Var_dump ($arr);

$arr = $result->fetch_assoc (); Reads a bar, returns an associative array

Var_dump ($arr);

$arr = $result->fetch_object (); Reads a bar, returns the object

Var_dump ($arr);

$arr = $result->fetch_all ();

foreach ($arr as $v) {

Dealing with gender
$sex = $v [2]? " Male ":" Female ";
Ethnic processing
$sql = "SELECT name from Nation where code= ' {$v [3]} '";
$re = $db->query ($sql);
$a = $re->fetch_row ();

echo "<tr>
<td>{$v [0]}</td>
<td>{$v [1]}</td>
<td>{$sex}</td>
<td>{$a [0]}</td>
<td>{$v [4]}</td>
</tr> ";
}

Then connect to the new PHP file, as follows

$db = new Mysqli ("localhost", "root", "123", "MyDB");
if (Mysqli_connect_error ()) {
Die ("Connection failed! ");
}
$sql = "INSERT into Xuanxiang values (0, ' 111111 ', ' a ', 1)";
if ($db->query ($sql)) {
echo "added successfully! ";
Echo $db->insert_id; Take the added primary key value
}else{
echo "Add failed! ";
}

Data access, accessing data using the MySQL class