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Detailed explanation of PHP pagination code (with examples)

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Release: 2016-07-25 08:52:24
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  1. // Establish database connection

  2. $link = mysql_connect("localhost", "mysql_user", "mysql_passWord")
  3. or die("Could not connect: " . mysql_error ());
  4. // Get the current page number
  5. if( isset($_GET['page']) ){
  6. $page = intval( $_GET['page'] );
  7. }
  8. else{
  9. $page = 1;
  10. }
  11. //Number of pages per page
  12. $PageSize = 10;
  13. //Get the total amount of data
  14. $sql = "select count(*) as amount from table";
  15. $result = mysql_query($sql);
  16. $row = mysql_fetch_row($result);
  17. $amount = $row['amount'];
  18. // Calculate how many pages there are in total
  19. if( $amount ){
  20. if( $amount < $page_size ){ $page_count = 1; } //If the total data amount is less than $PageSize, then there is only one page
  21. if( $amount % $page_size ){ //Take the remainder of the total data amount divided by the number of pages per page
  22. $page_count = (int)($ 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
  23. }else{
  24. $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
  25. }
  26. }
  27. else{
  28. $page_count = 0;
  29. }
  30. // Page turning link
  31. $page_string = '';
  32. if( $page == 1 ){
  33. $page_string .= 'First page|Previous page|';
  34. }
  35. else{
  36. $page_string .= 'First page |Previous page|';
  37. }
  38. if( ($page == $page_count) || ($page_count == 0) ){
  39. $page_string .= 'next page|last page';
  40. }
  41. else{
  42. $page_string .= '|Last page';
  43. }
  44. // Get data and return the result in two-dimensional array format
  45. if( $amount ){
  46. $sql = "select * from table order by id desc limit ". ($page-1)*$page_size .", $page_size";
  47. $result = mysql_query($sql);< ;/p>
  48. while ( $row = mysql_fetch_row($result) ){

  49. $rowset[] = $row;
  50. }
  51. }else{
  52. $rowset = array();
  53. }
  54. // 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
  55. ?>

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

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

  14. < p> function Pager($option)
  15. {
  16. global $db;
  17. $this->_setOptions($option);
  18. // Total number of items
  19. if ( !isset($this->numItems) )
  20. {
  21. $res = $db->query($this->sql);
  22. $this->numItems = $res->numRows();
  23. }
  24. // Total number of pages
  25. if ( $this-> ;numItems > 0 )
  26. {
  27. if ( $this->numItems < $this->PageSize ){ $this->numPages = 1; }
  28. if ( $this->numItems % $this- >PageSize )
  29. {
  30. $this->numPages= (int)($this->numItems / $this->PageSize) + 1;
  31. }
  32. else
  33. {
  34. $this->numPages = $ this->numItems / $this->PageSize;
  35. }
  36. }
  37. else
  38. {
  39. $this->numPages = 0;
  40. }

  41. switch ( $this-> CurrentPageID )

  42. {
  43. case $this->numPages == 1:
  44. $this->isFirstPage = true;
  45. $this->isLastPage = true;
  46. break;
  47. case 1:
  48. $this->isFirstPage = true;
  49. $this->isLastPage = false;
  50. break;
  51. case $this->numPages:
  52. $this->isFirstPage = false;
  53. $this->isLastPage = true;
  54. break;
  55. default :
  56. $this->isFirstPage = false;
  57. $this->isLastPage = false;
  58. }

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

  60. {
  61. if ( !$this->isLastPage ) { $this->NextPageID = $this->CurrentPageID + 1; }
  62. if ( !$this->isFirstPage ) { $this->PreviousPageID = $this-> CurrentPageID - 1; }
  63. }

  64. return true;

  65. }

  66. /***

  67. *
  68. * Return the database connection of the result set
  69. * 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
  70. * If the result set is not very large, you can Directly use getPageData to obtain the result in two-dimensional array format
  71. * The getPageData method also calls this method to obtain the result
  72. *
  73. ***/

  74. function getDataLink()

  75. {
  76. if ( $this->numItems )
  77. {
  78. global $db;

  79. $PageID = $this->CurrentPageID;

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

  83. return $link;

  84. }
  85. else
  86. {
  87. return false;
  88. }
  89. }
  90. /***

  91. *
  92. * Return the result set in the format of a two-dimensional array
  93. *
  94. ***/

  95. function getPageData()

  96. {
  97. if ( $this->numItems )
  98. {
  99. if ( $res = $ this->getDataLink() )
  100. {
  101. if ( $res->numRows() )
  102. {
  103. while ( $row = $res->fetchRow() )
  104. {
  105. $result[] = $row;
  106. }
  107. }
  108. else
  109. {
  110. $result = array();
  111. }

  112. return $result;

  113. }
  114. else
  115. {
  116. return false;
  117. }
  118. }
  119. else
  120. {
  121. return false;
  122. }
  123. }

  124. function _setOptions($option)

  125. {
  126. $allow_options = array(
  127. 'PageSize',
  128. 'CurrentPageID',
  129. 'sql',
  130. 'numItems '
  131. );

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

  133. {
  134. if ( in_array($key, $allow_options) && ($value != null) )
  135. {
  136. $this->$key = $value;
  137. }
  138. }

  139. return true;

  140. }
  141. }
  142. ?>

  143. Call example:

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

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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:

  1. Class MemberPager extends Pager
  2. {
  3. function showMemberList()
  4. {
  5. global $db;

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

  7. // Code to display results
  8. // ......
  9. }
  10. }
  11. /// Call
  12. if ( isset($_GET['page']) )
  13. {
  14. $page = (int)$_GET['page'];
  15. }
  16. else
  17. {
  18. $page = 1;
  19. }
  20. $sql = "select * from members order by id";
  21. $pager_option = array(
  22. "sql" => $sql,
  23. "PageSize" => 10,
  24. "CurrentPageID" => $page
  25. );
  26. if ( isset($_GET['numItems']) )
  27. {
  28. $pager_option['numItems' ] = (int)$_GET['numItems'];
  29. }
  30. $pager = @new MemberPager($pager_option);
  31. $pager->showMemberList();
  32. ?>

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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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