Enhanced version of phplib's DB class_PHP tutorial

/************************************ *************************************************** ******************************
In order to facilitate your own development and don’t want to use behemoths like ADODB and PEAR::DB,
Used on the basis of PHPLib DB class, refer to PEAR::DB class. The encapsulated DB class is simple, easy to use and very convenient.
MySQL is valid

[Connect to database]

//Include database processing class files
include_once("database.inc.php");

// Local database configuration
define("DB_HOST", "localhost"); //Database server
define("DB_USER_NAME", "root"); //Database user name
define("DB_USER_PASS", " "); //Password
define("DB_DATABASE", "test"); //Database

//Connect to local database
$db = new DB_Sql();
$db ->connect(DB_DATABASE, DB_HOST, DB_USER_NAME, DB_USER_PASS);

[Usage]

//Get all records
$sql = "SELECT * FROM table1";
$all_record = $db->get_all($sql);

//Get one
$sql = "SELECT * FROM table1 WHERE id = '1'";
$one_row = $db->get_one($sql);

//Page query, extract 20 records
$sql = "SELECT * FROM table1";
$page_record = $db-> limit_query($sql, $start=0, $offset=20, $order="ORDER BY id DESC");

//Extract the specified number of records
$sql = "SELECT * FROM table1 ";
$limit_record = $db->get_limit($sql,10);

//Count the number of records, count all types of students
$count = $db-> count("table1", "id", "type = 'student'");

//Insert a record
$info_array = array(
"name" => "heiyeluren" ,
"type" => "student",
"age" => "22",
"gender" => "boy"
);
$db- >insert("table1", $info_array);

//Update a record
$info_array = array(
"name" => "heiyeluren",
"type" => "teacher",
"age" => "22",
"gender" => "boy"
);
$db->update("table1" , $info_array, "name = 'heiyeluren'");

//Delete record
$db->delete("table1", "name = 'heiyeluren'");

//Execute a SQL without result set
$db->execute("DELETE FROM table1 WHERE name = 'heiyeluren'");

************ *************************************************** *********************************************/

/**
* File: database.inc.php
* Description: Database operation class
* Description: This library uses the PHPLib DB library as the core, while adding some practical methods, please refer to the comments for details
*/

class DB_Sql
{

/* public: connection parameters */
var $Host = "";
var $ Database = "";
var $User = "";
var $Password = "";

/* public: configuration parameters */
var $Auto_Free = 1; ## Set to 1 for automatic mysql_free_result()
var $Debug = 0; ## Set to 1 for debugging messages.
var $Halt_On_Error = "yes"; ## "yes" (halt with message), "no " (ignore errors quietly), "report" (ignore errror, but spit a warning)
var $PConnect = 0; ## Set to 1 to use persistent database connections
var $Seq_Table = "db_sequence";

/* public: result array and current row number */
var $Record = array();
var $Row;

/* public: current error number and error text */
var $Errno = 0;
var $Error = "";

/* public: this is an api revision, not a CVS revision. */
var $ type = "mysql";
//var $revision = "1.2";

  /* private: link and query handles */
  var $Link_ID  = 0;
  var $Query_ID = 0;

  var $locked   = false;      ## set to true while we have a lock

  /* public: constructor */
  function DB_Sql() {
    $this->query($query);
  }

  /* public: some trivial reporting */
  function link_id() {
    return $this->Link_ID;
  }

  function query_id() {
    return $this->Query_ID;
  }

  /* public: connection management */
  function connect($Database = "", $Host = "", $User = "", $Password = "") {
    /* Handle defaults */
    if ("" == $Database) 
      $Database = $this->Database;

    if ("" == $Host) 
      $Host     = $this->Host;

    if ("" == $User) 
      $User     = $this->User;

    if ("" == $Password) 
      $Password = $this->Password;

      
    /* establish connection, select database */
    if ( 0 == $this->Link_ID ) {

      if(!$this->PConnect) {
        $this->Link_ID = mysql_connect($Host, $User, $Password);
      } else {
        $this->Link_ID = mysql_pconnect($Host, $User, $Password); 
      }
      if (!$this->Link_ID) {
        $this->halt("connect($Host, $User, $Password) failed.");
        return 0;
      }

      if (!@mysql_select_db($Database,$this->Link_ID)) {
        $this->halt("cannot use database ".$Database);
        return 0;
      }
    }

    return $this->Link_ID;
  }

  /* public: discard the query result */
  function free() {
      @mysql_free_result($this->Query_ID);
      $this->Query_ID = 0;
  }

  /* public: perform a query */
  function query($Query_String) {
    /* No empty queries, please, since PHP4 chokes on them. */
    if ($Query_String == "")
      /* The empty query string is passed on from the constructor,
       * when calling the class without a query, e.g. in situations
       * like these: '$db = new DB_Sql_Subclass;'
       */
      return 0;

    if (!$this->connect()) {
      return 0; /* we already complained in connect() about that. */
    };

    # New query, discard previous result.
    if ($this->Query_ID) {
      $this->free();
    }

    if ($this->Debug)
      printf("Debug: query = %s
n", $Query_String);

    $this->Query_ID = @mysql_query($Query_String,$this->Link_ID);
    $this->Row   = 0;
    $this->Errno = mysql_errno();
    $this->Error = mysql_error();
    if (!$this->Query_ID) {
      $this->halt("Invalid SQL: ".$Query_String);
    }

    # Will return nada if it fails. That's fine.
    return $this->Query_ID;
  }

  /* public: walk result set */
  function next_record() {
    if (!$this->Query_ID) {
      $this->halt("next_record called with no query pending.");
      return 0;
    }

    $this->Record = @mysql_fetch_array($this->Query_ID);
    $this->Row   += 1;
    $this->Errno  = mysql_errno();
    $this->Error  = mysql_error();

    $stat = is_array($this->Record);
    if (!$stat && $this->Auto_Free) {
      $this->free();
    }
    return $stat;
  }

  /* public: position in result set */
  function seek($pos = 0) {
    $status = @mysql_data_seek($this->Query_ID, $pos);
    if ($status)
      $this->Row = $pos;
    else {
      $this->halt("seek($pos) failed: result has ".$this->num_rows()." rows.");

      /* half assed attempt to save the day, 
       * but do not consider this documented or even
       * desireable behaviour.
       */
      @mysql_data_seek($this->Query_ID, $this->num_rows());
      $this->Row = $this->num_rows();
      return 0;
    }

    return 1;
  }

  /* public: table locking */
  function lock($table, $mode = "write") {
    $query = "lock tables ";
    if(is_array($table)) {
      while(list($key,$value) = each($table)) {
        // text keys are "read", "read local", "write", "low priority write"
        if(is_int($key)) $key = $mode;
        if(strpos($value, ",")) {
          $query .= str_replace(",", " $key, ", $value) . " $key, ";
        } else {
          $query .= "$value $key, ";
        }
      }
      $query = substr($query, 0, -2);
    } elseif(strpos($table, ",")) {
      $query .= str_replace(",", " $mode, ", $table) . " $mode";
    } else {
      $query .= "$table $mode";
    }
    if(!$this->query($query)) {
      $this->halt("lock() failed.");
      return false;
    }
    $this->locked = true;
    return true;
  }

  function unlock() {

    // set before unlock to avoid potential loop
    $this->locked = false;

    if(!$this->query("unlock tables")) {
      $this->halt("unlock() failed.");
      return false;
    }
    return true;
  }

  /* public: evaluate the result (size, width) */
  function affected_rows() {
    return @mysql_affected_rows($this->Link_ID);
  }

  function num_rows() {
    return @mysql_num_rows($this->Query_ID);
  }

  function num_fields() {
    return @mysql_num_fields($this->Query_ID);
  }

  /* public: shorthand notation */
  function nf() {
    return $this->num_rows();
  }

  function np() {
    print $this->num_rows();
  }

  function f($Name) {
    if (isset($this->Record[$Name])) {
      return $this->Record[$Name];
    }
  }

  function p($Name) {
    if (isset($this->Record[$Name])) {
      print $this->Record[$Name];
    }
  }

  /* public: sequence numbers */
  function nextid($seq_name) {
    /* if no current lock, lock sequence table */
    if(!$this->locked) {
      if($this->lock($this->Seq_Table)) {
        $locked = true;
      } else {
        $this->halt("cannot lock ".$this->Seq_Table." - has it been created?");
        return 0;
      }
    }

    /* get sequence number and increment */
    $q = sprintf("select nextid from %s where seq_name = '%s'",
               $this->Seq_Table,
               $seq_name);
    if(!$this->query($q)) {
      $this->halt('query failed in nextid: '.$q);
      return 0;
    }

    /* No current value, make one */
    if(!$this->next_record()) {
      $currentid = 0;
      $q = sprintf("insert into %s values('%s', %s)",
                 $this->Seq_Table,
                 $seq_name,
                 $currentid);
      if(!$this->query($q)) {
        $this->halt('query failed in nextid: '.$q);
        return 0;
      }
    } else {
      $currentid = $this->f("nextid");
    }
    $nextid = $currentid + 1;
    $q = sprintf("update %s set nextid = '%s' where seq_name = '%s'",
               $this->Seq_Table,
               $nextid,
               $seq_name);
    if(!$this->query($q)) {
      $this->halt('query failed in nextid: '.$q);
      return 0;
    }

    /* if nextid() locked the sequence table, unlock it */
    if($locked) {
      $this->unlock();
    }

    return $nextid;
  }

  /* public: return table metadata */
  function metadata($table = "", $full = false) {
    $count = 0;
    $id    = 0;
    $res   = array();

    /*
     * Due to compatibility problems with Table we changed the behavior
     * of metadata();
     * depending on $full, metadata returns the following values:
     *
     * - full is false (default):
     * $result[]:
     *   [0]["table"]  table name
     *   [0]["name"]   field name
     *   [0]["type"]   field type
     *   [0]["len"]    field length
     *   [0]["flags"]  field flags
     *
     * - full is true
     * $result[]:
     *   ["num_fields"] number of metadata records
     *   [0]["table"]  table name
     *   [0]["name"]   field name
     *   [0]["type"]   field type
     *   [0]["len"]    field length
     *   [0]["flags"]  field flags
     *   ["meta"][field name]  index of field named "field name"
     *   This last one could be used if you have a field name, but no index.
     *   Test:  if (isset($result['meta']['myfield'])) { ...
     */

    // if no $table specified, assume that we are working with a query
    // result
    if ($table) {
      $this->connect();
      $id = @mysql_list_fields($this->Database, $table);
      if (!$id) {
        $this->halt("Metadata query failed.");
        return false;
      }
    } else {
      $id = $this->Query_ID; 
      if (!$id) {
        $this->halt("No query specified.");
        return false;
      }
    }

    $count = @mysql_num_fields($id);

    // made this IF due to performance (one if is faster than $count if's)
    if (!$full) {
      for ($i=0; $i<$count; $i++) {
        $res[$i]["table"] = @mysql_field_table ($id, $i);
        $res[$i]["name"]  = @mysql_field_name  ($id, $i);
        $res[$i]["type"]  = @mysql_field_type  ($id, $i);
        $res[$i]["len"]   = @mysql_field_len   ($id, $i);
        $res[$i]["flags"] = @mysql_field_flags ($id, $i);
      }
    } else { // full
      $res["num_fields"]= $count;

      for ($i=0; $i<$count; $i++) {
        $res[$i]["table"] = @mysql_field_table ($id, $i);
        $res[$i]["name"]  = @mysql_field_name  ($id, $i);
        $res[$i]["type"]  = @mysql_field_type  ($id, $i);
        $res[$i]["len"]   = @mysql_field_len   ($id, $i);
        $res[$i]["flags"] = @mysql_field_flags ($id, $i);
        $res["meta"][$res[$i]["name"]] = $i;
      }
    }

    // free the result only if we were called on a table
    if ($table) {
      @mysql_free_result($id);
    }
    return $res;
  }

  /* public: find available table names */
  function table_names() {
    $this->connect();
    $h = @mysql_query("show tables", $this->Link_ID);
    $i = 0;
    while ($info = @mysql_fetch_row($h)) {
      $return[$i]["table_name"]      = $info[0];
      $return[$i]["tablespace_name"] = $this->Database;
      $return[$i]["database"]        = $this->Database;
      $i++;
    }

    @mysql_free_result($h);
    return $return;
  }

  /* private: error handling */
  function halt($msg) {
    $this->Error = @mysql_error($this->Link_ID);
    $this->Errno = @mysql_errno($this->Link_ID);

    if ($this->locked) {
      $this->unlock();
    }

    if ($this->Halt_On_Error == "no")
      return;

    $this->haltmsg($msg);

    if ($this->Halt_On_Error != "report")
      die("Session halted.");
  }

  function haltmsg($msg) {
    printf("Database error: %s
n", $msg);
    printf("MySQL Error: %s (%s)
n",
      $this->Errno,
      $this->Error);
  }

 
 //----------------------------------
 // 模块: 自定义函数
 // 功能: 部分实用的数据库处理方法
 // 作者: heiyeluren
 // 时间: 2005-12-26
 //----------------------------------

 /**
* Method: execute($sql)
* Function: Execute a SQL statement, mainly for SQL that does not return a result set
* Parameters: $sql The SQL statement that needs to be executed, for example: execute("DELETE FROM table1 WHERE id = '1'")
* Return: Returns True if the update is successful, False if the update fails
*/
 function execute($sql)
 {
  if (empty($sql))
  {
   $this->error("Invalid parameter");
  }
  if (!$this->query($sql))
  {
   return false;
  }
  return true;
 }

 /**
* Method: get_all($sql)
* Function: Get all records of SQL execution
* Parameter: $sql The SQL that needs to be executed, for example: get_all("SELECT * FROM Table1")
* Return: Return a two-dimensional array containing all query results
*/
 function get_all($sql)
 {
  $this->query($sql);
  $result_array = array();
  while($this->next_record())
  {

   $result_array[] = $this->Record;
  }
  if (count($result_array)<=0)
  {
   return 0;
  }
  return $result_array;
 }

 /**
* Method: get_one($sql)
* Function: Get a record of SQL execution
* Parameter: $sql The SQL that needs to be executed, for example: get_one("SELECT * FROM Table1 WHERE id = '1 '")
* Returns: Returns a one-dimensional array containing a query result
*/
 function get_one($sql)
 {
  $this->query($sql);
  if (!$this->next_record())
  {
   return 0;
  }
  return $this->Record;
 }

 /**
* Method: get_limit($sql, $limit)
* Function: Get the specified number of records for SQL execution
* Parameters:
* $sql The SQL that needs to be executed, for example: SELECT * FROM Table1
* $limit The number of records that need to be limited
* For example, if you need to obtain 10 records, get_limit("SELECT * FROM Table1", 10);
*
* Return: Return including all query results A two-dimensional array of
*/
 function get_limit($sql, $limit)
 {
  $this->query($sql);
  $result_array = array();
  for ($i=0; $i<$limit&&$this->next_record(); $i++)
  {
   $result_array[] = $this->Record;
  }
  if (count($result_array) <= 0)
  {
   return 0;
  }
  return $result_array;
 }

 /**
* Method: limit_query($sql, $start=0, $offset=20, $order="")
* Function: Get the specified number of records executed by SQL for paging
* Parameters:
* $sql The SQL that needs to be executed, for example: SELECT * FROM Table1
* $start The starting number of records, the default is 0
* $offset The offset of the record, the default is 20
* $order sorting method, the default is empty, for example: ORDER BY id DESC
* For example, you need to get records from 0 to 10 and sort them by ID number, get_limit("SELECT * FROM Table1", 0, 10 , "ORDER BY id DESC");
*
* Returns: Returns a two-dimensional array
containing all query results*/
 function limit_query($sql, $start=0, $offset=20, $order="")
 {
  $sql = $sql ." $order  LIMIT $start,$offset";
  $this->query($sql);
  $result = array();
  while($this->next_record())
  {
   $result[] = $this->Record;
  }
  if (count($result) <=0 )
  {
   return 0;
  }
  return $result;
 }

 /**
* Method: count($table,$field="*", $where="")
* Function: Total number of data in the statistics table
* Parameters:
* $table needs statistics Table name
* $field The field that needs to be counted, the default is *
* $where conditional statement, the default is empty
* For example, count all users younger than 20 years old according to ID, count("user_table" , "id", "user_age < 20")
*
* Returns: Returns the number of statistical results
*/
 function count($table,$field="*", $where="")
 {
  $sql = (empty($where) ? "SELECT COUNT($field) FROM $table" : "SELECT COUNT($field) FROM $table WHERE $where");
  $result = $this->get_one($sql);
  if (!is_array($result))
  {
   return 0;
  }
  return $result[0];
 }

 /**
* Method: insert($table,$dataArray)
* Function: Insert a record into the table
* Parameters:
* $table The name of the table to be inserted
* $dataArray required Insert an array of fields and values. The key is the field name and the value is the field value. For example: array("user_name"=>"Zhang San", "user_age"=>"20 years old");
* For example Insert user Zhang San, age is 20, insert("users", array("user_name"=>"Zhang San", "user_age"=>"20 years old"))
*
* Return: Returns True if the record is inserted successfully, False if failed
*/
 function insert($table,$dataArray)
 {
  if (!is_array($dataArray) || count($dataArray)<=0)
  {
   $this->error("Invalid parameter");
  }
  while(list($key,$val) = each($dataArray))
  {
   $field .= "$key,";
   $value .= "'$val',";
  }
  $field = substr($field, 0, -1);
  $value = substr($value, 0, -1);
  $sql = "INSERT INTO $table ($field) VALUES ($value)";
  if (!$this->query($sql))
  {
   return false;
  }
  return true;
 }

 /**
* Method: update($talbe, $dataArray, $where)
* Function: Update a record
* Parameters:
* $table The name of the table that needs to be updated
* $dataArray required Update the array of fields and values. The key is the field name and the value is the field value. For example: array("user_name"=>"Zhang San", "user_age"=>"20 years old");
* $where Conditional statement
* For example For example, the user named Zhang San is updated to be Li Si, and the age is 21
* update("users", array("user_name"=>"Zhang San", "user_age"=> ;"20 years old"), "user_name='Zhang San'")
*
* Return: True if the update is successful, False if the update fails
*/
 function update($talbe, $dataArray, $where)
 {
  if (!is_array($dataArray) || count($dataArray)<=0)
  {
   $this->error("Invalid parameter");
  }
  while(list($key,$val) = each($dataArray))
  {
   $value .= "$key = '$val',";
  }
  $value = substr($value, 0, -1);
  $sql = "UPDATE $talbe SET $value WHERE $where";
  if (!$this->query($sql))
  {
   return false;
  }
  return true;
 }

 /**
* Method: delete($table, $where)
* Function: Delete a record
* Parameters:
* $table The name of the table where the record needs to be deleted
* $where The record needs to be deleted Conditional statement
* For example, if you want to delete the user named Zhang San, delete("users", "user_name='Zhang San'")
*
* Return: Return True if the update is successful, if it fails Return False
*/
 function delete($table, $where)
 {
  if (empty($where))
  {
   $this->error("Invalid parameter");
  }
  $sql = "DELETE FROM $table WHERE $where";
  if (!$this->query($sql))
  {
   return false;
  }
  return true;
 }

 /**
* Method: error($msg="")
* Function: Abort the script after displaying the error message
* Parameter: $msg The error message to be displayed
* Return: None
*/
 function error($msg="")
 {
  echo "Error: $msgn
n";
  exit();
 }

 /**
* Method: get_insert_id()
* Function: Get the last inserted ID
* Parameters: No parameters
* Return: Return ID on successful closing, 0 on failure
*/
 function get_insert_id()
 {
  return mysql_insert_id($this->Link_ID);
 }

 /**
* Method: close()
* Function: Close the current database connection
* Parameters: No parameters
* Return: Return true if successful, false if failed
*/
 function close()
 {
  return mysql_close($this->Link_ID);
 } 
}
?>