1. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition1  Wiley and the book authors, 2002 PHP Bible Chapter 15: PHP/MySQL Database Functions

2. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition2  Wiley and the book authors, 2002 Summary Connecting to MySQL Making queries Fetching data Getting data about data Using multiple connections Error checking Creating databases

3. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition3  Wiley and the book authors, 2002 Connecting to MySQL After you've designed and setup your MySQL database, you can begin to write PHP scripts that interact with it The basic command to initiate a MySQL connection is resource mysql_connect ( [string server [, string username [, string password [, bool new_link [, int client_flags]]]]]) Returns a MySQL link identifier on success, or FALSE on failure  Typically, you will supply a server name, username, and password when connecting to the specified database $db = mysql_connect('sql.gettelco.com','MGMT380b','MGMT380b'); Once you've established the connection to the specified server, you need to connect to a particular database on that server  bool mysql_select_db ( string database_name [, resource link_identifier]) sets the current active database on the server that's associated with the specified link identifier. If no link identifier is specified, the last opened link is assumed. mysql_select_db('MGMT380b',$db) or die('Could not connect to MGMT380b');

4. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition4  Wiley and the book authors, 2002 Making MySQL Queries A database query from PHP is basically a MySQL command wrapped up in a tiny PHP function resource resource mysql_query ( string query [, resource link_identifier]) sends a query to the currently active database on the server that's associated with the specified link identifier. If no link identifier is specified, the last opened link is used. This is where the workhorses of SELECT, INSERT, UPDATE, and DELETE will be executed. The MySQL commands to CREATE or DROP a table can also be used with this PHP function, but you can't CREATE or DROP a database $sql = 'SELECT * FROM catalog WHERE (category = "1")'; $query_handle = mysql_query($sql,$db);  The main reason you want to break up the query into 2 lines like this is so that if you get an error, you can retrieve and print or log the exact query that caused the problem.

5. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition5  Wiley and the book authors, 2002 Making MySQL Queries (cont.) If you are making a SELECT statement with a large number of records which will be returned (e.g. several thousand or more), you can use the following command which consumes less memory on the server and allows you to begin working on the data returned without waiting for the entire dataset to be retrieved resource mysql_unbuffered_query ( string query [, resource link_identifier]) sends a SQL query query to MySQL, without fetching and buffering the result rows automatically

6. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition6  Wiley and the book authors, 2002 Making MySQL Queries (cont.) If your query was in INSERT, UPDATE, DELETE, CREATE TABLE, or DROP TABLE and returned TRUE, you can use this command to see how many rows were changed by the query int mysql_affected_rows ( [resource link_identifier]) returns the number of rows affected by the last INSERT, UPDATE or DELETE query associated with link_identifier If your query was a SELECT statement, the value returned from mysql_query is a resource called a result identifier. This is a unique identifier for each SELECT statement executed. If you want to see the number of rows returned by the SELECT, use int mysql_num_rows ( resource result) returns the number of rows in a result set. This command is only valid for SELECT statements. $num_rows = mysql_num_rows($query_result);

7. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition7  Wiley and the book authors, 2002 Fetching Data Sets One thing that often seems to temporarily stymie new PHP users is the whole concept of fetching data from PHP It would be logical to assume the result of a query would be the desired data, but that is not the way PHP works What actually happens is that a mysql_query() command pulls the data out of the database and sends a receipt back to PHP reporting on the status of the operation At this point, the data exists in purgatory that is immediately accessible from neither MySQL nor PHP It requires one of the mysql_fetch functions to make the data from a successful SELECT statement fully available to PHP

8. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition8  Wiley and the book authors, 2002 Fetching Data Sets (cont.) The "fetching" functions are: array mysql_fetch_row ( resource result) fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0 object mysql_fetch_object ( resource result) returns an object with properties that correspond to the fetched row, or FALSE if there are no more rows array mysql_fetch_assoc ( resource result) returns an associative array that corresponds to the fetched row, or FALSE if there are no more rows array mysql_fetch_array ( resource result [, int result_type]) is an extended version of mysql_fetch_row(). In addition to storing the data in the numeric indices of the result array, it also stores the data in associative indices, using the field names as keys bool mysql_data_seek ( resource result_identifier, int row_number) moves the internal row pointer of the MySQL result associated with the specified result identifier to point to the specified row number

9. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition9  Wiley and the book authors, 2002 Fetching Data Sets (cont.) Typically, when retrieving data from an SQL SELECT query, you will want to use either mysql_fetch_array() or mysql_fetch_assoc() since it provides you the ability to access the fields returned by their field name rather than the specific offset as mysql_fetch_row() requires This way, if modifications are made to the order of the fields in the database or new fields are added (or deleted), you may not have to modify your code for accessing the data in the individual fields Also, in queries which result in very large numbers of fields returned, it can be extremely difficult to determine exactly which offset the field you want is located at

10. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition10  Wiley and the book authors, 2002 Fetching Data Sets (cont.) For example, this is an actual SQL query used in one of my applications: SELECT cdr_id, Record_ID, DateStamp, CONCAT(Time_Of_Record_Hours,":",Time_Of_Record_Minutes,":",Time_Of_Record_Seconds,".",Time_Of_Record_Seconds_100) AS Time_Of_Record, LEFT(Calling_NPA_Digits,Calling_NPA_Length) AS Calling_NPA, LEFT(Calling_Party_Number_Digits,IF(Calling_Party_Number_Length<3,Calling_Party_Number_Length,3)) AS Calling_Party_NXX, LEFT(Combined_Calling_NPA_Party_Number_Digits,Combined_Calling_NPA_Party_Number_Length-4) AS Calling_Party_NPANXX, SUBSTRING(Calling_Party_Number_Digits,4,IF(Calling_Party_Number_Length<7,Calling_Party_Number_Length-3,4)) AS Calling_Party_Station, LEFT(Calling_Party_Number_Digits,Calling_Party_Number_Length) AS Calling_Party_Number, LEFT(Combined_Calling_NPA_Party_Number_Digits,Combined_Calling_NPA_Party_Number_Length) AS ANI, LEFT(Called_NPA_Digits,Called_NPA_Length) AS Called_NPA, LEFT(Called_Party_Number_Digits,IF(Called_Party_Number_Length<3,Called_Party_Number_Length,3)) AS Called_Party_NXX, LEFT(Combined_Called_NPA_Party_Number_Digits,Combined_Called_NPA_Party_Number_Length-4) AS Called_Party_NPANXX, SUBSTRING(Called_Party_Number_Digits,4,IF(Called_Party_Number_Length<7,Called_Party_Number_Length-3,4)) AS Called_Party_Station, LEFT(Called_Party_Number_Digits,Called_Party_Number_Length) AS Called_Party_Number, LEFT(Combined_Called_NPA_Party_Number_Digits,Combined_Called_NPA_Party_Number_Length) AS DNIS, LEFT(Originators_Charge_Number_Digits,Originators_Charge_Number_Length) AS Originators_Charge_Number, LEFT(Terminating_Number_Digits,Terminating_Number_Length) AS Terminating_Number, CONCAT(Originating_Line_Shelf,":",Originating_Line_Card,":",Originating_Line_DS1,":",Originating_Line_DS0) AS Originating_Line, CONCAT(Terminating_Line_Shelf,":",Terminating_Line_Card,":",Terminating_Line_DS1,":",Terminating_Line_DS0) AS Terminating_Line, Incoming_Trunk_Group_Number AS Incoming_Trunk_Group, Outgoing_Trunk_Group_Number AS Outgoing_Trunk_Group, Incoming_Signaling_Protocol, Outgoing_Signaling_Protocol, Time_Of_Record_Hours AS Answer_Time_I_Hour, CONCAT(Answer_Time_I_Hour,":",Answer_Time_I_Minute,":",Answer_Time_I_Seconds,".",Answer_Time_I_Seconds_100) AS Answer_Time_I, CONCAT(Carrier_Connect_Time_Hour,":",Carrier_Connect_Time_Minute,":",Carrier_Connect_Time_Seconds,".",Carrier_Connect_Time_Seconds_100) AS Carrier_Connect_Time, CONCAT(Disconnect_Time_Hour,":",Disconnect_Time_Minute,":",Disconnect_Time_Seconds,".",Disconnect_Time_Seconds_100) AS Disconnect_Time, Conversation_Time_I_Minute*60 + Conversation_Time_I_Seconds + Conversation_Time_I_Seconds_100/100 AS Conversation_Time_I, Carrier_Elapsed_Time_Minute*60 + Carrier_Elapsed_Time_Seconds + Carrier_Elapsed_Time_Seconds_100/100 AS Carrier_Elapsed_Time, Call_Duration_Minute*60 + Call_Duration_Seconds + Call_Duration_Seconds_100/100 AS Call_Duration, (Call_Duration_Minute*60 + Call_Duration_Seconds + Call_Duration_Seconds_100/100) - (Conversation_Time_I_Minute*60 + Conversation_Time_I_Seconds + Conversation_Time_I_Seconds_100/100) AS Answer_Delay, Line_Information, Called_Party_Number_Digit_Type, Call_Handling_Code, Terminator_Type, Caller_ID_Status, CNAM_Status, SAC_Translation_Type, SAC_Translation_Status, SAC_Translation_CIC, LEFT(SAC_Translation_Digits,SAC_Translation_Length) AS SAC_Translation, LNP_Status, LEFT(LRN_Digits,LRN_Length) AS LRN, Called_Party_Offhook_Indicator, Emergency_Service_Call_Indicator, Carrier_Code, LEFT(Country_Code_Digits,Country_Code_Length) AS Country_Code, Overseas_Indicator, ICINC_Trunk_Group_Number, Dialing_Presubscription_Indicator, Timing_Guard_Flag, Short_Called_Party_Offhook_Indicator, Long_Duration_Call_Indicator, Number_Times_CID_Information_Delivered, Number_Times_CID_Information_Unavalable, Jurisdiction_Information_Parameter, Terminating_Access_Carrier_Code, Cause_Value FROM CSX21_CDR_2004 WHERE ((Combined_Calling_NPA_Party_Number_Digits like "618434____%"))

11. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition11  Wiley and the book authors, 2002 Fetching Data Sets (cont.) The following example takes the result of any SQL SELECT query and prints out the result in an HTML table print(' '); $header_printed = false; while ($row = mysql_fetch_assoc($result_handle)) { if (!$header_printed) { print (' '); foreach ($row as $field_name => $val) print(' '.$field_name.' '); print (' '); $header_printed = true; } print (' '); foreach ($row as $val) print (' '.$val.' '); print (' '); } print(' ');

12. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition12  Wiley and the book authors, 2002 Fetching Data Sets (cont.) The following example prints data from each named field returned from the query, "SELECT ItemID, Title, Price, Inventory, Description, PictureURL FROM catalog WHERE (Category = '1')" while ($row = mysql_fetch_assoc($result_handle)) { print (" ${row['ItemID']} ${row['Title']} \$${row['Price']} ${row['Inventory']} <FONT SIZE=\"-1\" ${row['Description']} "); }

13. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition13  Wiley and the book authors, 2002 Getting data about data PHP offers built-in functions to help you learn the name of the table in which your data resides, the data type handled by a particular column, or the number of the row into which you just inserted data In most cases, you need a higher level of security into the database or table you are accessing in order to use these functions than is required for just SELECT statements The MySQL metadata functions fall into two major categories:  Functions that return information about the previous operation  E.g. int mysql_insert_id ( [resource link_identifier]) returns the ID generated for an AUTO_INCREMENT column by the previous INSERT query  Functions that return information about the database structure in general  E.g. string mysql_field_type ( resource result, int field_offset) returns the type of data stored at the field located at field_offset. The field type will be one of "int", "real", "string", "blob", and others

14. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition14  Wiley and the book authors, 2002 Multiple connections Unless you have a specific reason to required multiple connections, you only need to make one database connection per PHP script (consequently, you will not need to specify the link_identifier in most function calls) If you're querying two or more completely separate database servers, you will need to create multiple connections (e.g. SELECT from the slave and UPDATE to the master) If this is required, simply hang onto the value returned by mysql_connect calls and use these in the appropriate link_identifier arguments in the mysql functions

15. _______________________________________________________________________________________________________________ PHP Bible, 2 nd Edition15  Wiley and the book authors, 2002 Building in Error-Checking This section could have been titled "Die, die, die!" because the main error- checking function is actually called die(). die() is not a MySQL-specific function, it simply terminates the script and returns a string of your choice Since PHP no longer prints error messages for database connections or queries by default, it is important to die with a meaningful message unless you want your visitors to be left wondering what happened Particularly useful during the development and debugging phases, and located in places where they can easily be commented out or routed to an error log, the following functions can be useful for determining why your script is not functioning the way you expected string mysql_error ( [resource link_identifier]) returns the error text from the last MySQL function, or '' (the empty string) if no error occurred int mysql_errno ( [resource link_identifier]) returns the error number from the last MySQL function, or 0 (zero) if no error occurred $handle = mysql_query($sql) or die('ERROR: '.mysql_error().' in '.$sql);