PHP ==> Database

== PHP is working with SQL database.

　　= = Database deconstruction:

Database server ==> database ==> table ==> record ==> field ==> information

It can be understood as follows:

Database Server ====> a book

Database ====> A page of paper in the book

Table ====> A table drawn on paper

Record each row on the ====> table

field ====> each column on the table

Information ====> the contents of each table

= = Database Common operations

　　= = Add data

1, connecting to the database (if using a server, change localhost to the server's IP)
Span style= "font-size:14pt" >                          &N Bsp             address        account   password     Corresponding database
$db = new Mysqli (' root ', ' 168168 ', '

3. Perform insert data operation: Execute an SQL statement that inserts data
Insert fixed format: "insert into table name (Field 1, Field 2, Field 3, Field 4) VALUES (" Content 1 "," Content 2 "," Content 3 ","content 4 ",)"
$sql = 'INSERT into Users (username,passwd,tel,addtime) VALUES (". $username. '", "'. MD5 ($PASSWD). '", "'. $tel. '". Date (' y-m-d h:i:s '). ')';
　　　　The content must correspond with the field one by one

4. Execute SQL statement to insert data into the database
$r = $db->query ($sql);

5. Close the database
$db->close ();

= = query data

1. Connect to the database (if using a server, change localhost to the server's IP)
Address account password corresponding database
$db = new mysqli (' localhost ', ' root ', ' 168168 ', ' user ');

2. The encoding of the setting data is not between UTF8:UTF and 8-
$db->query (' SET namds UTF8 ');

3. Perform insert data operation: Execute an SQL statement that inserts data

{The field to be queried, if you want to query all fields, fill in the * number } table name judgment Statement, Judge query that record, do not fill in the query all

$sql = 'SELECT id,username,passwd,tel,addtime from users WHERE Username = "'. $_post[' username ']." ';

4. Execute SQL statement query data
$r = $db->query ($sql);

5, the results of the query by associative array to save the way
$arr = $r->fetch_array (mysqli_assoc);

6. The corresponding value can be accessed by means of array access subscript

$arr [' username ']==> get username

7. Close the database
$db->close ();

= = Delete data

1. Connect to the database (if using a server, change localhost to the server's IP)
Address account password corresponding database
$db = new mysqli (' localhost ', ' root ', ' 168168 ', ' user ');

2. The encoding of the setting data is not between UTF8:UTF and 8-
$db->query (' SET namds UTF8 ');

3. Perform insert data operation: Execute an SQL statement that inserts data

Keyword keyword table name determine the criteria to delete that record, it must be the only condition

$sql = 'DELETE from users WHERE id = '. ( int) $id;

Execute DELETE statement
$r = $db->query ($sql);

4. Close the database
$db->close ();

= = Modify Data

1. Connect to the database (if using a server, change localhost to the server's IP)
Address account password corresponding database
$db = new mysqli (' localhost ', ' root ', ' 168168 ', ' user ');

2. The encoding of the setting data is not between UTF8:UTF and 8-
$db->query (' SET namds UTF8 ');

3. Perform insert data operation: Execute an SQL statement that inserts data

Keyword table name modification field = "New content" field = "new content" field = "New Content" the one that must be changed

$sql = 'UPDATE users SET username= '. $username. ' ",passwd=" '. MD5 ($PASSWD). ' ", tel= "'. $tel. ' WHERE id = '. ( int) $id. ' ";

Execute DELETE statement
$r = $db->query ($sql);

4. Close the database
$db->close ();

PHP ==> Database