1. SQL in higher level languages

2. SQL in higher level languages
Why do we want to use SQL in a higher level language?
Read in data from file, manipulate data before insert into relation
Loop until the EOF
read values from file – higher level code
manipulate values with higher level code
insert into relation values (SQL)
End loop
must read in values into C/C++ variables then use those values to insert using SQL
still need SQL statement to insert, select tuples

3. Why cont’d
Compute results based on result from query e.g. generate a report
Query database (SQL)
Compute results from query
Print results
must be able to manipulate results from SQL query, but mismatch between higher level language and SQL
sets versus one record at a time

4. Provide a user interface (Web) for SQL if the current one is lacking
Prompt user for query
Send query to DBMS (SQL)
Receive results
Display results to user
need to accept queries from user - create SQL queries

5. To do this? Given the query: Select * From department, employee
Where dno=dnumber and lname=??
What is needed?
Variables in which to i) specify a select condition or table to use ii) variable to place result (:Host variables)
Processing of result table (cursors)
Data structure for communicating with DBS in case of errors (SQLCA)
What if we want to process any query typed in? (Dynamic SQL)
Also must connect to the DB, authorized by DBMS
Must specify where to find the DB, the user login and the user PW

6. To do this Embedded SQL Precede each statement with EXEC SQL
2. Programming language that controls a software application
PHP, Go, etc.
3. Platform specific classes, interfaces
Oracle’s OLE
4. Platform independent classes, interfaces
JDBC

7. 2. PHP (and MYSQL)

8. PHP
Personal Home Page tools publicly released 1995 by R. Lerdorf (Danish-Canadian)
In 1998 became PHP: Hypertext Preprocessor
Creates DYNAMIC web pages
HTML traditionally static
Contents regenerated every time visit or reload site
(e.g. can include current time)

9. PHP PHP is a scripting language
Script like a dialogue for play interpreted by actors
Because it is interpreted?
Strong at communicating with program components written in other languages
E.g. can embed PHP statements within HTML

10. PHP
Takes input from a file or stream containing text and PHP instructions
Outputs stream of data for display
MySQL, support for SQLite, performance enhancements
SQLite – ACID compliant embedded relational DB contained in small C programming library. Source code in public domain. Entire DB stored as a single file on a host machine.
PHP 7 – Now available

11. PHP Resembles C in structure
Requires semicolons after each statement ;
Types are (booleans, integers, strings, etc.)
Syntax (For/While/If)
Assignment is right to left ($num = 56;)
Object-Oriented (Class support, inheritance, virtuals, polymorphism)
Functions!

12. PHP Variables begin with $ sign ($name = "John Doe";)
No explicit declaration of variable types
Introduction of “lazy” functions (foreach, explode, mail)
No Function Overloading
“Hidden” functions-within-a-function
Compiled/interpreted during every page load
Documented!
Echo for output
Concatenate is dot .

13. PHP - specifics Delimiters: <?php ?> or just <? ?>
PHP parses code within delimiters
Code outside delimiter sent to output, not parsed
Block comments /* */
Inline comments // #

14. Sample code
<?php // do not put a space between ? and php Echo "Hello CS457"; // can use either " or ' ?> To run this, only need to specify a link to this program - Example

15. PHP Web Specific: Dynamic HTML based on user-defined logic
Interact and process a form’s action
Process URL Parameters
Easy Database Integration
For example – MySQL!!

16. MySQL MySQL is a relational DBMS
Has many of the same capabilities as traditional DBMSs (newest releases)
MySQL queries mostly the same as SQL in Oracle (subsidiary of Sun)
Popular for web databases
It’s freeware!
“Monty” Widenius founder of MySQL –sold it to Sun (bought by Oracle) for $1B

17. PHP – procedural versus OO
My examples are procedural

18. Some php mysql functions
Connecting to MySQL through PHP
mysqli_connect ("IP_address", "login", "pw") //returns $link_id
mysqil_select_db ($link_id, "name_db") //assume same as login
mysqli_query ($link_id, $query)
Executes a query, place result in variable, like a cursor
Resource specifies a connection, otherwise last connection opened used
Returns a special variable holding a reference to external resource

19. Some php mysql functions
mysqli_fetch_array ($result, how)
Traverses through cursor of query result
Returns array corresponding to fetched row, moves pointer to next row
“how” is either mysqli_assoc (use col. names) or mysqli_num (use index number) or mysqli_both
mysqli_error ($link_id) $link not needed for connect
Returns error message from previous sql operation
mysqli_num_fields ($link, $result)
Returns number of columns in table (fields in recordset)

20. <?php
error_reporting(E_ALL); ini_set("display_errors", "1");
$link=mysqli_connect("cs-sql2014.ua-net.ua.edu", "mybamaID", "CWID");
if (!$link) {die("Not connected: ". mysqli_error()); } // see if connected
mysqli_select_db($link, 'login') or die('Cannot select database');
$query = 'CREATE TABLE testit( '.
'id INT NOT NULL, '.
'age int)';
$result = mysqli_query($link, $query);
if(!$result) {die( 'Error in SQL: ' . mysqli_error($link));}
echo "table created";
mysqli_close($link);
?>

22. <?php
error_reporting(E_ALL); ini_set("display_errors", "1");
echo "Welcome to Vrbsky's DB";
// Connect to MySQL
$link = mysqli_connect("cs-sql2014.ua-net.ua.edu", "mybamaID", "CWID");
if (!$link) {die('Not connected: '. mysqli_error()); } // see if connected
// Select DB will use
mysqli_select_db($link, 'login') or die ('Could not select database'); // see if worked
// Now the query
$query = "Select * from testit"; // testit has 2 columns, id and age
$result = mysqli_query($link, $query);
if (!$result) {die( 'Error in SQL: ' . mysqli_error($link));}
// process results using cursor
while ($row = mysqli_fetch_array($result)) {
echo "<hr>"; //horizontal line
echo "id: ". $row["id"] . "<br />";
echo "age: " . $row["age"] . "<br />"; }
mysqli_free_result ($result);
mysqli_close($link); // disconnecting from MySQL
?>

24. Accessing result rows // Using an index
while($row = mysqli_fetch_array($result, MYSQLI_NUM)) {
echo “ID:{$row[0]} <br>" .
“Age: {$row[1]} <br><br>"; }

26. Updated final project
HW#8 posted
Friday – come to class extra credit, bring a friend and get additional extra credit

27. Forms and input Can use HTML to create forms
Interaction with form results in php code executing (e.g. send query to DB)

28. HTML code
In our ex3.html, code uses HTML form to ask for input values to a table
When user inputs values, event (action) occurs and php code is executed
To use those values in php file, must use $_POST[‘var_name’]
Like a host variable

29. $_POST function <form method="post" action="example.php">
variables from a form will be placed into $_POST
$_ POST is an associative array (key, value)
Index into array is form data name
Info sent from form
POST is a superglobal variable, available in all scopes
With POST no limits on the amount of info to send
Different from $_GET function where
Info sent is displayed in browser’s address bar
Max 100 characters

30. HTML and PHP and MYSQL ex3.html
<html> </head> <center> <!- The following line results in php code executed after input values in form -> <form method="post" action="ex3.php"> <table> <tr><td align="left">ID</td> <td><input type="text" name="id"></td> </tr> <tr><td align="left">Age</td> <td><input type="text" name="age" size="15"></td> <tr><colspan="2"> <p align="center"> <input type="submit" value="Enter record"> </td> </table> </form> </center> </html>

31. PHP code
PHP code places values input from form into its own local variables
Connects to database
Inserts values into tables
Prints out values

32. ex3.php
<?php
error_reporting(E_ALL); ini_set("display_errors", "1");
// This is example3.php used in previous .htm code
$link = mysqli_connect("cs-sql2014.ua-net.ua.edu", "mybamaID", "CWID");
if (!$link) {die('Not connected: '. mysqli_error()); }
mysqli_select_db($link, 'login') or die ('Could not select database');
//have 2 host variables
$id= $_POST['id'];
$age = $_POST['age'];
//the query
$query = "insert into testit values ('$id', '$age')";
$result = mysqli_query($link, $query);
if (!$result) {die('SQL error: ' . mysqli_error($link));}
mysqli_close($link);
print "<html><body><center>";
print "<p>You have just entered this record<p>";
print "ID: $id<br>";
print "Age: $age";
print "</body></html>";
?>

34. Our set up
Two machines
cs457.ua.edu - php/html login: your_bama_id Password: your_bama_pw
cs-sql2014.ua-net.ua.edu - MySQL server machine login: your_bama_id
Password: CWID

35. html
php 1
cs457.ua.edu – ssh use mybama id/pw 4 2 3
Your DB using MySQL
cs-sql2014.ua-net.ua.edu –
use mybama id/CWID

36. Connecting to MySQL
You can connect to MySQL through a higher level language: .php, go, ruby on rails, etc.
write PHP code to:
insert tuples into your tables/views Or
You can connect to MySQL directly using a client tool

37. MySQL Client Tools
You can connect to MySQL directly using a client tool
Host is: cs-sql2014.ua-net.ua.edu  
User:  your_bama_id
Password: your CWID
Database: you may have to create a database, use same name as user login

38. MySQL Client Tools
You can use a toolset to create tables and insert tuples into your tables on cs-sql2014.ua-net.ua.edu
Possible toolsets:
HeidiSQL
Sequel Pro (Mac)
PhpMyAdmin
Toad:
But only good for 30 days

39. Test PHP on cs457.ua.edu
Create your php and html files on cs457.ua.edu
using an editor, e.g. vi
Make sure the file is on the cs457.ua.edu machine in the public_html directory – chmod 755 so can execute
Sample program:
<?php
Echo “Hello World”;
?>
To run it, from a web browser, type in:
For example, I use:

40. Running Examples
Next copy some of the programs from examples in these slides using php and mySQL and run them.
Make sure you change the login, password and database to yours
Make sure you create any needed tables for the examples.

41. HW#8
Need 2 files:
1 for html 1 for php
You can test your SQL statements first using MySQL client (or whatever)
To grant permission to others use their bama_id, e.g., for me it is svrbsky

42. Lots of great links on the web to get into
Disadvantage: How to determine what is error?

43. Stopped here

44. Dynamic query

45. Example HTML and PHP ex4.html
<body>
<center>
<form method="post" action="ex4.php">
<!-- places values in associative array called $_POST -->
<font size="18">Complete the Select Statement</font><br> Select
<input type="text" name="select" size="60" value=" " ><br>
<input type="submit" value="Get Query"></form>
<table border="1">
</table></center></body></html>

46. <?php //This is example4.php referenced in previous .html code
error_reporting(E_ALL); ini_set("display_errors", "1");
$link = mysqli_connect("cs-sql2014.ua-net.ua.edu", "mybamaID", "CWID");
if(!$link) { die('Not connected: '.mysqli_error());}
mysqli_select_db($link, “login");
// isset tests if the value of the variable is set
if(isset($_POST['select'])) {
//$select = 'select '.$_POST['select'];
//echo $select;
//can have problems with col=.string., so must get rid of \.s inserted by php for mysql|
$select = stripslashes('select '.$_POST['select']);
echo $select;
$result = mysqli_query($link, $select);
if(!$result) { echo mysqli_error($link); }
else {
while($row = mysqli_fetch_array($result, MYSQLI_NUM)) {
echo "<hr>"; // horizontal line
echo "<tr>";
for($count = 0; $count < 10; $count++) {
if(isset($row[$count])) echo " <td>{$row[$count]}</td>";
if(!isset($row[$count]) && isset($row[++$count])) {
echo "<td></td>"; $count--; } }
echo "</tr>";
?>

48. 1. Embedded SQL

49. Embedded SQL
Embedded SQL – not used much these days – basis for all others
Precede each statement with EXEC SQL
Embedded Select statement
EXEC SQL Select [distinct] expr {, expr}
into host_var {, host_var}
From table_name [alias] {, table_name [alias]}
[Where search_cond]
[Group by col {, col}]
[Having search_cond]

50. Embedded SQL Only returns 1 value - EXEC SQL select lname, salary
into :lname, :sal
From employee
Where ssn= ;
If Returns multiple values -
char emp_name[50][20];
int emp_number[50];
float salary[50];
EXEC SQL SELECT ENAME, EMPNO, SAL
INTO :emp_name, :emp_number, :salary FROM EMP WHERE SAL > 1000;

51. Embedded SQL EXEC SQL declare c1 cursor for Select essn, hours
From WORKS_ON
Where pno = :proj_id;
EXEC SQL open c1;
EXEC SQL fetch c1 into :essn_id, :hrs;
while (sqlca.sqlcode == 0) // checks for EOT {
cout << essn_id << “ “ << hrs << endl;
EXEC SQL fetch c1 into :essn_id, :hrs;          
  };

52. Must precompile this code
Precompiler generates DBMS API calls for SQL and comments out SQL statements

53. . 3. Platform specific classes, interfaces
Oracle’s OLE
a middleware product manufactured by Oracle Corporation that allows native access (no ODBC) to Oracle databases from client applications via Microsoft OLE (Object Linking and Embedding) and COM (Component Object Model)
Native Access to Oracle and only Oracle databases
Runs slightly faster than ODBC access
Some people feel it is VERY convenient

54. OLE
Use OLE Classes
Example - execute SQL statements directly with the ExecuteSQL method.
db.ExecuteSQL("insert into project values (:projectName, :projectNumber, :projectLocation, :departmentNumber)")

55. OLE Using a cursor: ODynaset results(db, "Select * from employee");
cout << "salary" << endl;
cout << "========" << endl;
double salary;
while (!results.IsEOF()) {
if (results.GetFieldValue ("salary", &salary) == OFAILURE) {
cout << db.GetServerErrorText() << endl;
// example of character string // char first [10];
// results.GetFieldValue("fname", first, 10); }
else { cout << salary << endl;
results.MoveNext(); }

56. JDBC 4. Platform independent classes, interfaces JDBC