SQL Statements

SQL Statements

Basic Operations

Web Technology

INSERT INTO

• Insert a record into a table

• Insert record(s) from a table right into another table

INSERT INTO table (col1, col2, col3) VALUES(val1, val2, val3);

INSERT INTO tct_phone (std_fname, std_lname, std_phone) VALUES(“Khaosai”, “Galaxy”, “088-123-4567”);

INSERT INTO tct_phone (std_fname, std_lname, std_phone) select fname, lname, phone from tct_students

where academic_year = ‘2552’;

Edit a Record

• Modify a record

• Modify Khaosai’s phone number

UPDATE table SET field1=’val1’, field2=’val2’, field3=’val3’ WHERE condition;

UPDATE tct_phone SET std_phone=’089-123-1234’

WHERE std_fname = ‘Khaosai’ and std_lname = ‘Galaxy’;

Delete Record(s)

• Delete selected record(s)

• Delete Khaosai’s record from the table

– This will delete all records with firstname ‘Khaosai’

– This will delete all records with lastname ‘Galaxy’

DELETE FROM table WHERE condition;

DELETE FROM tct_phone WHERE std_fname = ‘Khaosai’;

DELETE FROM tct_phone WHERE std_lname = ‘Galaxy’;

Delete Record(s)

• Do a better job with AND

• Anyway, this would be a better choice by using primary key as the target

• Note: avoid this;

– it will delete all records in the tatble

DELETE FROM tct_phone WHERE std_id = 20;

DELETE FROM tct_phone WHERE std_fname = ‘Khaosai’

AND std_lname = ‘Galaxy’;

DELETE FROM tct_phone;

Creating Links for Edit and Delete

<?print("<TD>

[ <a href='edit_phone.php?std_id=$name_row[0]'>Edit</a> | <a href='#‘ onClick=\"del_confirm('std_id=$name_row[0]');\">Delete</a>]

</TD>");?>

Creating Javascript for Del Confirmation

<script language="JavaScript">function del_confirm(to_del){

var bDel = confirm("Do you really want to delete this record?");if(bDel){

var str = "del_phone_action.php?" + to_del; window.location = str;}

}</script>

Add a Record Form

Sample Code of Add Phone Action

<?$fname = $_POST['txtFName'];$lname = $_POST['txtLName'];$phone = $_POST['txtPhone'];$section = $_POST['rdSection'];

$query = “INSERT INTO tct_phone (std_fname, std_lname, std_phone, section) VALUES ('$fname', '$lname', '$phone', '$section');";

$result = mysql_query($query);if(mysql_affected_rows() == 1) {

echo "Add new phone successfully!";}else echo "<font color='#FF0000'>An error occurs.</font>";?>

Edit an Existing Record Form

Keep in mind, we have to fill in the form with selected record first. So, we have to make a query (select) on the selected target, and then generatethe code (HTML+PHP) as following slide.

Sample Code of Edit Form

<TABLE width="312"><TR><TD bgcolor="#AAAAAA"><strong>Firstname</strong></TD><TD><input type="text" name="txtFName" value="<? echo $std_fname;?>"></TD></TR><TR><TD bgcolor="#AAAAAA"><strong>Lastame</strong></TD><TD><input type="text" name="txtLName" value="<? echo $std_lname;?>"></TD></TR><TR><TD bgcolor="#AAAAAA"><strong>Phone</strong></TD><TD><input type="text" name="txtPhone" value="<? echo $std_phone;?>"></TD></TR><TR><TD bgcolor="#AAAAAA"><strong>Section</strong></TD> <TD> <input type="radio" name="rdSection" value="1R" <? echo ($std_section=="1R")?" checked":"";?>>RA <input type="radio" name="rdSection" value="1T" <? echo ($std_section=="1T")?" checked":"";?>>TA </TD></TR><TR><TD colspan="2" align="center">

<input type="hidden" name="std_id" value="<? echo $std_id; ?>"><input type="reset" name="reset" value="Cancel"><input type="submit" name="submit" value="Submit"></TD>

</TR></TABLE>

Sample Code of Edit Phone Action

<?$std_id = $_POST['std_id'];$fname = $_POST['txtFName'];$lname = $_POST['txtLName'];$phone = $_POST['txtPhone'];$section = $_POST['rdSection'];

$query = "UPDATE tct_phone SET std_fname='$fname', std_lname='$lname', std_phone='$phone', section='$section‘ WHERE std_id=$std_id;";

$result = mysql_query($query);if(mysql_affected_rows() == 1) {

echo "Edit record successfully!";}else echo "<font color='#FF0000'>An error occurs.</font>";?>

Sample Code of Delete Phone Action

<?$std_id = $_REQUEST['std_id'];

$query = "DELETE FROM tct_phone WHERE std_id=$std_id;";$result = mysql_query($query);if(mysql_affected_rows() == 1) {

echo "Delete record successfully!";}else echo "<font color='#FF0000'>An error occurs.</font>";

?>

Note: We should have a way to check for confirmation before really deleting the record.In this case, we use Javascript to prevent unintentional deletion.Anyway, a better way is to have used a submission of POST type. This will be given by in-class discussion

Setting Database Permissions

• Web visitor– SELECT only

• Contributor– SELECT, INSERT, and maybe UPDATE

• Editor– SELECT, INSERT, UPDATE, and maybe DELETE (and maybe

GRANT)

• Root– SELECT, INSERT, UPDATE, DELETE, GRANT, and DROP