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v5:userguide:mysql_tutorial [2016/02/18 22:53] – Fix formatting and layout dregadv5:userguide:mysql_tutorial [2018/06/27 16:09] (current) – [Moving from MySQL to ADOdb] increase title level dregad
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 </WRAP> </WRAP>
  
-====== Tutorial ====== + 
-===== Moving from MySQL to ADOdb =====+====== Moving from MySQL to ADOdb ======
  
 <WRAP indent> <WRAP indent>
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 PHP is all about creating dynamic web-sites with the least fuss and the most fun. To create these websites we need to use databases to retrieve login information, to splash dynamic news onto the web page and store forum postings. So let's say we were using the popular MySQL database for this. Your company has done such a fantastic job that the Web site is more popular than your wildest dreams. You find that MySQL cannot scale to handle the workload; time to switch databases. PHP is all about creating dynamic web-sites with the least fuss and the most fun. To create these websites we need to use databases to retrieve login information, to splash dynamic news onto the web page and store forum postings. So let's say we were using the popular MySQL database for this. Your company has done such a fantastic job that the Web site is more popular than your wildest dreams. You find that MySQL cannot scale to handle the workload; time to switch databases.
  
-Unfortunately in PHP every database is accessed slightly differently. To connect to MySQL, you would use ''mysql_connect();'' when you decide to upgrade to Oracle or Microsoft SQL Server, you would use ''ocilogon()'' or ''mssql_connect()'' respectively. What is worse is that the parameters you use for the different connect functions are different also.. One database says po-tato, the other database says pota-to. Oh-oh.+Unfortunately in PHP every database is accessed slightly differently. To connect to MySQL, you would use ''mysqli_connect();'' when you decide to upgrade to Oracle or Microsoft SQL Server, you would use ''ocilogon()'' or ''mssql_connect()'' respectively. What is worse is that the parameters you use for the different connect functions are different also.. One database says po-tato, the other database says pota-to. Oh-oh.
  
 ===== Let's NOT call the whole thing off ===== ===== Let's NOT call the whole thing off =====
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 <code php> <code php>
 // Section 1 // Section 1
-$db = mysql_connect("localhost", "root", "password"); +$db = mysqli_connect("localhost", "root", "password"); 
-mysql_select_db("mydb",$db);+mysqli_select_db("mydb",$db);
  
 // Section 2 // Section 2
-$result = mysql_query("SELECT * FROM employees",$db);+$result = mysqli_query("SELECT * FROM employees",$db);
 if ($result === false) die("failed"); if ($result === false) die("failed");
  
 // Section 3 // Section 3
-while ($fields = mysql_fetch_row($result)) {+while ($fields = mysqli_fetch_row($result)) {
     for ($i=0, $max=sizeof($fields); $i < $max; $i++) {     for ($i=0, $max=sizeof($fields); $i < $max; $i++) {
         print $fields[$i].' ';         print $fields[$i].' ';
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 // Section 1 // Section 1
 include("adodb.inc.php"); include("adodb.inc.php");
-$db = NewADOConnection('mysql'); +$db = newADOConnection('mysqli'); 
-$db->Connect("localhost", "root", "password", "mydb");+$db->connect("localhost", "root", "password", "mydb");
  
 // Section 2 // Section 2
-$result = $db->Execute("SELECT * FROM employees");+$result = $db->execute("SELECT * FROM employees");
 if ($result === false) die("failed"); if ($result === false) die("failed");
  
 // Section 3 // Section 3
 while (!$result->EOF) { while (!$result->EOF) {
-    for ($i=0, $max=$result->FieldCount(); $i < $max; $i++) {+    for ($i=0, $max=$result->fieldCount(); $i < $max; $i++) {
         print $result->fields[$i].' ';         print $result->fields[$i].' ';
     }     }
-    $result->MoveNext();+    $result->moveNext();
     print "<br>\n";     print "<br>\n";
 } }
 </code> </code>
    
-Now porting to Oracle is as simple as changing the second line to ''NewADOConnection('oracle')''. Let's walk through the code...+Now porting to Oracle is as simple as changing the second line to ''newADOConnection('oracle')''. Let's walk through the code...
  
 ==== Connecting to the Database ==== ==== Connecting to the Database ====
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 <code php> <code php>
 include("adodb.inc.php"); include("adodb.inc.php");
-$db = NewADOConnection('mysql'); +$db = newADOConnection('mysql'); 
-$db->Connect("localhost", "root", "password", "mydb");+$db->connect("localhost", "root", "password", "mydb");
 </code> </code>
  
-The connection code is a bit more sophisticated than MySQL's because our needs are more sophisticated. In ADOdb, we use an object-oriented approach to managing the complexity of handling multiple databases. We have different classes to handle different databases. If you aren't familiar with object-oriented programing, don't worry -- the complexity is all hidden away in the NewADOConnection() function.+The connection code is a bit more sophisticated than MySQL's because our needs are more sophisticated. In ADOdb, we use an object-oriented approach to managing the complexity of handling multiple databases. We have different classes to handle different databases. If you aren't familiar with object-oriented programing, don't worry -- the complexity is all hidden away in the ''NewADOConnection()'' function.
  
-To conserve memory, we only load the PHP code specific to the database you are connecting to. We do this by calling NewADOConnection(databasedriver). Legal database drivers include mysql, mssql, oracle, oci8, postgres, sybase, vfp, access, ibase and many others.+To conserve memory, we only load the PHP code specific to the database you are connecting to. We do this by calling ''NewADOConnection(databasedriver)''. Legal database drivers include mysql, mssql, oracle, oci8, postgres, sybase, vfp, access, ibase and many others.
  
-Then we create a new instance of the connection class by calling NewADOConnection(). Finally we connect to the database using $db->Connect().+Then we create a new instance of the connection class by calling ''NewADOConnection()''. Finally we connect to the database using ''$db%%->%%Connect()''.
  
 ==== Executing the SQL ==== ==== Executing the SQL ====
  
 <code php> <code php>
-$result = $db->Execute("SELECT * FROM employees");+$result = $db->execute("SELECT * FROM employees");
 if ($result === false) die("failed"); if ($result === false) die("failed");
 </code> </code>
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 while (!$result->EOF) while (!$result->EOF)
 { {
-    for ($i=0, $max=$result->FieldCount(); $i < $max; $i++)+    for ($i=0, $max=$result->fieldCount(); $i < $max; $i++)
         print $result->fields[$i].' ';         print $result->fields[$i].' ';
-    $result->MoveNext();+    $result->moveNext();
     print "<br>\n";     print "<br>\n";
 } }
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 The paradigm for getting the data is that it's like reading a file. For every line, we check first whether we have reached the end-of-file (EOF). While not end-of-file, loop through each field in the row. Then move to the next line (MoveNext) and repeat. The paradigm for getting the data is that it's like reading a file. For every line, we check first whether we have reached the end-of-file (EOF). While not end-of-file, loop through each field in the row. Then move to the next line (MoveNext) and repeat.
  
-The ''$result->fields[]'' array is generated by the PHP database extension. Some database extensions do not index the array by field name. To force indexing by name - that is associative arrays - use the ''$ADODB_FETCH_MODE'' global variable.+The ''$result%%->%%fields[]'' array is generated by the PHP database extension. Some database extensions do not index the array by field name. To force indexing by name - that is associative arrays - use the ''$ADODB_FETCH_MODE'' global variable.
  
 <code php> <code php>
 $ADODB_FETCH_MODE = ADODB_FETCH_NUM; $ADODB_FETCH_MODE = ADODB_FETCH_NUM;
-$rs1 = $db->Execute('select * from table');+$rs1 = $db->execute('select * from table');
 $ADODB_FETCH_MODE = ADODB_FETCH_ASSOC; $ADODB_FETCH_MODE = ADODB_FETCH_ASSOC;
-$rs2 = $db->Execute('select * from table');+$rs2 = $db->execute('select * from table');
 print_r($rs1->fields); // shows array([0]=>'v0',[1] =>'v1') print_r($rs1->fields); // shows array([0]=>'v0',[1] =>'v1')
 print_r($rs2->fields); // shows array(['col1']=>'v0',['col2'] =>'v1') print_r($rs2->fields); // shows array(['col1']=>'v0',['col2'] =>'v1')
 </code> </code>
  
-As you can see in the above example, both recordsets store and use different fetch modes based on the $ADODB_FETCH_MODE setting when the recordset was created by ''Execute()''.+As you can see in the above example, both recordsets store and use different fetch modes based on the ''$ADODB_FETCH_MODE'' setting when the recordset was created by ''Execute()''.
  
 ===== ADOConnection ===== ===== ADOConnection =====
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 ===== Other Useful Functions ===== ===== Other Useful Functions =====
  
-''$recordset->Move($pos)'' scrolls to that particular row. ADOdb supports forward scrolling for all databases. Some databases will not support backwards scrolling. This is normally not a problem as you can always cache records to simulate backwards scrolling. +  * ''$recordset%%->%%move($pos)'' scrolls to that particular row. ADOdb supports forward scrolling for all databases. Some databases will not support backwards scrolling. This is normally not a problem as you can always cache records to simulate backwards scrolling. 
-'' + 
-$recordset->RecordCount()'' returns the number of records accessed by the SQL statement. Some databases will return -1 because it is not supported.+  * ''$recordset%%->%%recordCount()'' returns the number of records accessed by the SQL statement. Some databases will return -1 because it is not supported.
  
-''$recordset->GetArray()'' returns the result as an array.+  * ''$recordset%%->%%getArray()'' returns the result as an array.
  
-''rs2html($recordset)'' is a function that generates a HTML table based on the $recordset passed to it. An example with the relevant lines in bold:+  * ''rs2html($recordset)'' is a function that generates a HTML table based on the $recordset passed to it. An example with the relevant lines in bold:
  
 <code php> <code php>
 include('adodb.inc.php'); include('adodb.inc.php');
 include('tohtml.inc.php'); /* includes the rs2html function */ include('tohtml.inc.php'); /* includes the rs2html function */
-$conn = ADONewConnection('mysql'); +$conn = newADOConnection('mysqli'); 
-$conn->PConnect('localhost','userid','password','database'); +$conn->pConnect('localhost','userid','password','database'); 
-$rs = $conn->Execute('select * from table');+$rs = $conn->execute('select * from table');
 rs2html($rs); /* recordset to html table */  rs2html($rs); /* recordset to html table */ 
 </code> </code>
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 When you move to another database, your insert might no longer work. When you move to another database, your insert might no longer work.
  
-The first problem is that each database has a different default date format. MySQL expects YYYY-MM-DD format, while other databases have different defaults. ADOdb has a function called [[v5:reference:dbdate]] that addresses this issue by converting converting the date to the correct format.+The first problem is that each database has a different default date format. MySQL expects YYYY-MM-DD format, while other databases have different defaults. ADOdb has a function called [[v5:reference:connection:dbdate|dbDate()]] that addresses this issue by converting converting the date to the correct format.
  
-The next problem is that the //don't// in the Note needs to be quoted. In MySQL, we use ''don\'t'' but in some other databases (Sybase, Access, Microsoft SQL Server) we use ''don''t''. The [[v5:reference:qstr]] function addresses this issue.+The next problem is that the //don't// in the Note needs to be quoted. In MySQL, we use ''don\'t'' but in some other databases (Sybase, Access, Microsoft SQL Server) we use ''don%%''%%t''. The [[v5:reference:connection:qStr()]] function addresses this issue.
  
 So how do we use the functions? Like this: So how do we use the functions? Like this:
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    . $db->dbDate($TheDate) .','    . $db->dbDate($TheDate) .','
    . $db->qStr($Note).")";    . $db->qStr($Note).")";
-$db->Execute($sql);+$db->execute($sql);
  
 </code> </code>
  
-ADOdb also supports [[v5:reference:affected_rows|''$connection->affected_rows()'']] (returns the number of rows affected by last update or delete) and [[v5:reference:insert_id|''$recordset->insert_id()'']] (returns last autoincrement number generated by an insert statement). Be forewarned that not all databases support the two functions.+ADOdb also supports ''[[v5:reference:connection:affected_rows|$connection->affected_rows()]]'' (returns the number of rows affected by last update or delete) and ''[[v5:reference:connection:insert_id|$recordset->insert_id()]]'' (returns last autoincrement number generated by an insert statement). Be forewarned that **not all databases support the two functions**.
  
-===== MetaTypes =====+==== MetaTypes ====
  
 You can find out more information about each of the fields (I use the words fields and columns interchangeably) you are selecting by calling the recordset method ''FetchField($fieldoffset)''. This will return an object with 3 properties: //name//, //type// and //max_length//. You can find out more information about each of the fields (I use the words fields and columns interchangeably) you are selecting by calling the recordset method ''FetchField($fieldoffset)''. This will return an object with 3 properties: //name//, //type// and //max_length//.
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 For example: For example:
 <code php> <code php>
-$recordset = $conn->Execute("select adate from table"); +$recordset = $conn->execute("select adate from table"); 
-$f0 = $recordset->FetchField(0);+$f0 = $recordset->fetchField(0);
 </code> </code>
  
-Then ''$f0->name'' will hold 'adata', ''$f0->type'' will be set to 'date'. If the //max_length// is unknown, it will be set to -1.+Then ''$f0%%->%%name'' will hold 'adata', ''$f0%%->%%type'' will be set to 'date'. If the //max_length// is unknown, it will be set to -1.
  
 One problem with handling different databases is that each database often calls the same type by a different name. For example a timestamp type is called //datetime// in one database and //time// in another. So ADOdb has a special ''MetaType($type, $max_length)'' function that standardises the types to the following: One problem with handling different databases is that each database often calls the same type by a different name. For example a timestamp type is called //datetime// in one database and //time// in another. So ADOdb has a special ''MetaType($type, $max_length)'' function that standardises the types to the following:
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 <code php> <code php>
-$recordset = $conn->Execute("select adate from table"); +$recordset = $conn->execute("select adate from table"); 
-$f0 = $recordset->FetchField(0); +$f0 = $recordset->fetchField(0); 
-$type = $recordset->MetaType($f0->type, $f0->max_length);+$type = $recordset->metaType($f0->type, $f0->max_length);
 print $type; /* should print 'D' */ print $type; /* should print 'D' */
 </code> </code>
  
-===== Select Limit and Top Support =====+==== Select Limit and Top Support ====
  
-ADOdb has a function called [[v5:reference:selectlimit|''$connection->SelectLimit($sql,$nrows,$offset)'']] that allows you to retrieve a subset of the recordset. This will take advantage of native ''SELECT TOP'' on Microsoft products and ''SELECT ... LIMIT'' with PostgreSQL and MySQL, and emulated if the database does not support it.+ADOdb has a function called ''[[v5:reference:connection:selectlimit|$connection->SelectLimit($sql,$nrows,$offset)]]'' that allows you to retrieve a subset of the recordset. This will take advantage of native ''SELECT TOP'' on Microsoft products and ''SELECT ... LIMIT'' with PostgreSQL and MySQL, and emulated if the database does not support it.
  
-===== Caching Support =====+==== Caching Support ====
  
 ADOdb allows you to cache recordsets in your file system, and only requery the database server after a certain timeout period with  ADOdb allows you to cache recordsets in your file system, and only requery the database server after a certain timeout period with 
  
-  * ''$connection->CacheExecute($secs2cache,$sql)'' +  * ''$connection->cacheExecute($secs2cache,$sql)'' 
-  * ''$connection->CacheSelectLimit($secs2cache,$sql,$nrows,$offset)''.+  * ''$connection->cacheSelectLimit($secs2cache,$sql,$nrows,$offset)''.
  
-===== Session Handler Support =====+==== Session Handler Support ====
  
 ADOdb also supports session handlers. You can store your session variables in a database for true scalability using ADOdb. For further information, see the section on [[v5:session:session_index|Sessions]]. ADOdb also supports session handlers. You can store your session variables in a database for true scalability using ADOdb. For further information, see the section on [[v5:session:session_index|Sessions]].
v5/userguide/mysql_tutorial.1455832435.txt.gz · Last modified: 2017/04/21 11:39 (external edit)