PHP Connection Database

PHP Connection Database

1. Connect Database functions

Mysqli_connect ( hostname, username, password ) The return value is one of our connection objects if the connection fails the error returns false

2. Judging the error function

Mysqli_connect_error ( Connection object ) error message return error message

Mysqli_connect_errno ( Connection object ) error number 0 indicates successful connection without error

3. Select database Functions

mysqli_select_db ( Connection object, the name of the database to select ); If you choose to return successfully true otherwise return false

4. Select a character set

Mysqli_set_charset ( the Connection object, the character set to select ), or If the selection succeeds returns True False

5. preparing SQL Statements

6. sending SQL statements

Mysqli_query ( Connection object , s Q L statement to be sent ); successful getting an object failed to return false

7. Working with result sets

7.1 Gets the number of entries

a) mysqli_num_rows ( the sending of SQL successful objects ) is used to get the number of record bars in the query only Select statement uses

b) mysqli_affected_rows ( Connection object ) the number of affected rows in the previous MySQL operation is limited to Insert UPDATE DELETE operation using return value 1 number of successfully inserted bars -1 execution failed

7.2 getting the contents of a query result set

Mysqli_fetch_array ( sending Object ) Returns the result of the query as a mixed array, returning one

Mysqli_fetch_row ( sending Object ) returns The result of the query as an indexed array, returning one

Mysqli_fetch_assoc ( send Object ) returns The result of the query as a group of associative numbers returns one

7.3 When adding an operation we can get the ID of the last insert

MYSQLI_INSERT_ID ( Connection object ) returns the ID of the last insertion

8. Close the database

Mysqli_close ( Connection object )

PHP Kung fu Cheats day dragon Eight steps

1. Connect to the database

2. Judging errors

3. Select a database

4. Select a character Set

5. Preparing SQL statements

6. Sending SQL statements

7. Working with result sets

8. Close the database

1. Connect to the database

Mysqli_connect (' hostname ', ' username ', ' password ');

[Email protected]_connect (' localhost ', ' root ', ' 123456 ');

Var_dump ($link);

2. Judging errors

Mysqli_connect_error (Connection object) error message

Mysqli_connect_errno (Connection object) error number

echo Mysqli_connect_errno ($link);

echo Mysqli_connect_error ($link);

if (Mysqli_connect_errno ($link)) {

echo Mysqli_connect_error ($link); exit;

echo ' wrong reconnect '; exit;

}

3. Select a database

mysqli_select_db ($link, ' ss21 ');

4. Select a character Set

Mysqli_set_charset ($link, ' UTF8 ');

5. Preparing SQL statements

$sql = "Select id,name,sex,age,city from Info";

$sql = "INSERT into info (name) VALUES (NULL)";

6. Sending SQL statements

$result = Mysqli_query ($link, $sql);

7. Working with result sets

echo mysqli_num_rows ($result);

echo mysqli_affected_rows ($link);

8. Close the database

Mysqli_close ($link);

PHP Connection Database