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Home Backend Development PHP Tutorial Detailed explanation of PHP pagination code (with examples)

Detailed explanation of PHP pagination code (with examples)

Jul 25, 2016 am 08:52 AM

  3. // Establish database connection

  4. $link = mysql_connect("localhost", "mysql_user", "mysql_passWord")
  5. or die("Could not connect: " . mysql_error ());
  6. // Get the current page number
  7. if( isset($_GET['page']) ){
  8. $page = intval( $_GET['page'] );
  9. }
  10. else{
  11. $page = 1;
  12. }
  13. //Number of pages per page
  14. $PageSize = 10;
  15. //Get the total amount of data
  16. $sql = "select count(*) as amount from table";
  17. $result = mysql_query($sql);
  18. $row = mysql_fetch_row($result);
  19. $amount = $row['amount'];
  20. // Calculate how many pages there are in total
  21. if( $amount ){
  22. if( $amount < $page_size ){ $page_count = 1; } //If the total data amount is less than $PageSize, then there is only one page
  23. if( $amount % $page_size ){ //Take the remainder of the total data amount divided by the number of pages per page
  24. $page_count = (int)($ amount / $page_size) + 1; //If there is a remainder, the number of pages is equal to the total data amount divided by the number of pages, rounded up and plus one
  25. }else{
  26. $page_count = $amount / $page_size; //If If there is no remainder, the number of pages is equal to the total data amount divided by the number of each page
  27. }
  28. }
  29. else{
  30. $page_count = 0;
  31. }
  32. // Page turning link
  33. $page_string = '';
  34. if( $page == 1 ){
  35. $page_string .= 'First page|Previous page|';
  36. }
  37. else{
  38. $page_string .= 'First page |Previous page|';
  39. }
  40. if( ($page == $page_count) || ($page_count == 0) ){
  41. $page_string .= 'next page|last page';
  42. }
  43. else{
  44. $page_string .= '|Last page';
  45. }
  46. // Get data and return the result in two-dimensional array format
  47. if( $amount ){
  48. $sql = "select * from table order by id desc limit ". ($page-1)*$page_size .", $page_size";
  49. $result = mysql_query($sql);< ;/p>

  50. while ( $row = mysql_fetch_row($result) ){

  51. $rowset[] = $row;
  52. }
  53. }else{
  54. $rowset = array();
  55. }
  56. // None Contains the code for displaying the results, which is beyond the scope of the discussion. As long as you use foreach, you can easily display the results using the obtained two-dimensional array
  57. ?>

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4. OO style code Database connections are handled using the pear db class.

  4. // FileName: Pager.class.php
  5. // Paging class, this class is only used to process data structures and is not responsible for processing display
  6. Class Pager
  7. {
  8. var $PageSize; //Number of each page
  9. var $CurrentPageID; //Current page number
  10. var $NextPageID; //Next page
  11. var $PreviousPageID; //Previous page
  12. var $numPages; //Total number of pages
  13. var $numItems; //Total number of records
  14. var $isFirstPage; //Whether it is the first page
  15. var $isLastPage; //Whether it is the last page
  16. var $sql; //sql query statement

  17. < p> function Pager($option)
  18. {
  19. global $db;
  20. $this->_setOptions($option);
  21. // Total number of items
  22. if ( !isset($this->numItems) )
  23. {
  24. $res = $db->query($this->sql);
  25. $this->numItems = $res->numRows();
  26. }
  27. // Total number of pages
  28. if ( $this-> ;numItems > 0 )
  29. {
  30. if ( $this->numItems < $this->PageSize ){ $this->numPages = 1; }
  31. if ( $this->numItems % $this- >PageSize )
  32. {
  33. $this->numPages= (int)($this->numItems / $this->PageSize) + 1;
  34. }
  35. else
  36. {
  37. $this->numPages = $ this->numItems / $this->PageSize;
  38. }
  39. }
  40. else
  41. {
  42. $this->numPages = 0;
  43. }

  44. switch ( $this-> CurrentPageID )

  45. {
  46. case $this->numPages == 1:
  47. $this->isFirstPage = true;
  48. $this->isLastPage = true;
  49. break;
  50. case 1:
  51. $this->isFirstPage = true;
  52. $this->isLastPage = false;
  53. break;
  54. case $this->numPages:
  55. $this->isFirstPage = false;
  56. $this->isLastPage = true;
  57. break;
  58. default :
  59. $this->isFirstPage = false;
  60. $this->isLastPage = false;
  61. }

  62. if ( $this->numPages > 1 )

  63. {
  64. if ( !$this->isLastPage ) { $this->NextPageID = $this->CurrentPageID + 1; }
  65. if ( !$this->isFirstPage ) { $this->PreviousPageID = $this-> CurrentPageID - 1; }
  66. }

  67. return true;

  68. }

  69. /***

  70. *
  71. * Return the database connection of the result set
  72. * When the result set is relatively large, you can directly use this method to obtain the database connection, and then traverse outside the class, so the overhead is smaller
  73. * If the result set is not very large, you can Directly use getPageData to obtain the result in two-dimensional array format
  74. * The getPageData method also calls this method to obtain the result
  75. *
  76. ***/

  77. function getDataLink()

  78. {
  79. if ( $this->numItems )
  80. {
  81. global $db;

  82. $PageID = $this->CurrentPageID;

  83. < ;p> $from = ($PageID - 1)*$this->PageSize;
  84. $count = $this->PageSize;
  85. $link = $db->limitQuery($this->sql, $ from, $count); //Use the Pear DB::limitQuery method to ensure database compatibility

  86. return $link;

  87. }
  88. else
  89. {
  90. return false;
  91. }
  92. }

  93. /***

  94. *
  95. * Return the result set in the format of a two-dimensional array
  96. *
  97. ***/

  98. function getPageData()

  99. {
  100. if ( $this->numItems )
  101. {
  102. if ( $res = $ this->getDataLink() )
  103. {
  104. if ( $res->numRows() )
  105. {
  106. while ( $row = $res->fetchRow() )
  107. {
  108. $result[] = $row;
  109. }
  110. }
  111. else
  112. {
  113. $result = array();
  114. }

  115. return $result;

  116. }
  117. else
  118. {
  119. return false;
  120. }
  121. }
  122. else
  123. {
  124. return false;
  125. }
  126. }

  127. function _setOptions($option)

  128. {
  129. $allow_options = array(
  130. 'PageSize',
  131. 'CurrentPageID',
  132. 'sql',
  133. 'numItems '
  134. );

  135. foreach ( $option as $key => $value )

  136. {
  137. if ( in_array($key, $allow_options) && ($value != null) )
  138. {
  139. $this->$key = $value;
  140. }
  141. }

  142. return true;

  143. }
  144. }
  145. ?>

  146. Call example:

  147. // FileName: test_pager.php
  148. // The code to establish a database connection using the pear db class is omitted
  149. require "Pager .class.php";
  150. if ( isset($_GET['page']) )
  151. {
  152. $page = (int)$_GET['page'];
  153. }
  154. else
  155. {
  156. $page = 1;
  157. }
  158. $sql = "select * from table order by id";
  159. $pager_option = array(
  160. "sql" => $sql,
  161. "PageSize" => 10,
  162. "CurrentPageID" => $page
  163. );
  164. if ( isset($_GET['numItems']) )
  165. {
  166. $pager_option['numItems'] = (int)$_GET['numItems'];
  167. }
  168. $pager = @new Pager($pager_option );
  169. $data = $pager->getPageData();
  170. if ( $pager->isFirstPage )
  171. {
  172. $turnover = "Homepage|Previous Page|";
  173. }
  174. else
  175. {
  176. $turnover = "Homepage|Previous Page|";
  177. }
  178. if ( $pager->isLastPage )
  179. {
  180. $turnover .= "Next Page |Last page";
  181. }
  182. else
  183. {
  184. $turnover .= "|Last page}
  185. ?>

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to explain two points: This class only processes data and is not responsible for display, because I think it is a bit reluctant to put both data processing and result display into one class. When displaying, the situation and requirements are changeable. It is better to process it according to the results given by the class. A better way is to inherit a subclass of its own based on the Pager class to display different paginations, such as displaying the user pagination list:

  4. Class MemberPager extends Pager
  5. {
  6. function showMemberList()
  7. {
  8. global $db;

  9. $data = $this- >getPageData();

  10. // Code to display results
  11. // ......
  12. }
  13. }
  14. /// Call
  15. if ( isset($_GET['page']) )
  16. {
  17. $page = (int)$_GET['page'];
  18. }
  19. else
  20. {
  21. $page = 1;
  22. }
  23. $sql = "select * from members order by id";
  24. $pager_option = array(
  25. "sql" => $sql,
  26. "PageSize" => 10,
  27. "CurrentPageID" => $page
  28. );
  29. if ( isset($_GET['numItems']) )
  30. {
  31. $pager_option['numItems' ] = (int)$_GET['numItems'];
  32. }
  33. $pager = @new MemberPager($pager_option);
  34. $pager->showMemberList();
  35. ?>

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Note: Due to the compatibility of different databases, the way to write a section of results in different databases is different. mysql: select * from table limit offset, rows pgsql: select * from table limit m offset n ... Therefore, when obtaining results in the class, you need to use the limitQuery method of the pear db class.



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