interface:
Using the interface ( interface ), you can specify a class method which must implement , but need not define the specific content of these methods.
The interface is defined by the interface keyword, like the definition of a standard of class, but the definition of all the methods are empty.
All methods defined in the interface must be public , which is characteristic of the interface.
To implement an interface, using implements operator . Class all the methods defined in the interface must be implemented, otherwise it will report a fatal error. Class can implement multiple interfaces, with a comma-separated names of the plurality of interfaces.
Database operations:
Step 1: Connect to the MySQL database server mysql -uroot -root
Step two: Select the database to operate (current database) use db_name
Step 3: Set the character set set names gbk
Step Four: Execute SQL statement: add, delete, change,
增加：INSERT INTO table_name(title,author,addate) VALUES(‘标题’,’admin’,now())
Delete: DELETE FROM table_name WHERE conditional expression
Modify: UPDATE table_name SET title = "new title" WHERE conditional expression
查询：SELECT * FROM table_name WHERE条件 ORDER BY LIMIT
Link MySQL : three ways
The difference between process-oriented and object-oriented : process-oriented is to analyze the steps needed to resolve them, and then use the function of these steps, step by step to achieve , when used one by one in turn call on it; object-oriented is to be a problem affairs broken down into each object, the purpose of creating an object is not to complete a step, but to Miao Xu a thing in the entire steps to resolve the problem of conduct.
Use PDO: need to switch more database
Query data:
$result = $conn->query($sql);
$ Result-> num_rows; Analyzing data returned
$ Result-> fetch_assoc () to be incorporated into the set associative arrays and cyclic output