如何在插入表之前删除表中的所有数据

首先我想删除表中的所有数据，然后它将插入新数据。我正在将.dbf fox pro表导入phpmyadmin，它正在工作。但问题是，当我再次导入它时，数据会翻倍。有人能帮我实现这一点吗？

这是我的密码。

<?php
include "config.sample.php";            // please copy the config.sample.php and edit the correct fields
include "classes/XBase/Table.php";
include "classes/XBase/Column.php";
include "classes/XBase/Record.php";
include "classes/DBFhandler.php";
use XBase'Table;
 // Initializing vars
ini_set( 'memory_limit', '2048M' );
set_time_limit( 0 );
$time_start = time();
$files = scandir($xbase_dir) or die ("Error! Could not open directory '$xbase_dir'.");
$conn = new mysqli($db_host, $db_uname, $db_passwd, $db_name) or die ("Error connecting to mysql $mysqli->connect_error");
foreach ($files as $file) {
  switch ($file) {
  case (preg_match("/dbf$/i", $file) ? true : false):
    print_r("DBF: $file'n");
    dbftomysql($file);
    break;
  default:
    print_r("Other file: $file'n");
  }
}
$time_end = time();
"'n'nImport finished! Time spent: ". round( ( $time_end - $time_start ) / 60, 2 ) ." minutes'n";
function dbftomysql($file) {
    // Path to dbase file
    global $xbase_dir;
    global $conn;
    global $die_on_mysql_error;
    $db_path = sprintf("%s/%s",$xbase_dir,$file);
    // Open dbase file
    $table = new Table($db_path);
    $tbl = substr($file,0,strlen($file)-4);
    print_r ("$tbl");
    $line = array();
    foreach ($table->getColumns() as $column) {
        print_r("'t$column->name ($column->type / $column->length)'n");
        switch($column->type) {
            case 'C':   // Character field
                $line[]= "`$column->name` VARCHAR($column->length)";
                break;
            case 'F':   // Floating Point
                $line[]= "`$column->name` FLOAT";
                break;
            case 'N':   // Numeric
                $line[]= "`$column->name` INT";
                break;
            case 'L':   // Logical - ? Y y N n T t F f (? when not initialized).
                $line[]= "`$column->name` TINYINT";
                break;
            case 'D':   // Date
                $line[]= "`$column->name` DATE";
                break;
            case 'T':   // DateTime
                $line[]= "`$column->name` DATETIME";
                break;
            case 'M':   // Memo type field
            default:
                $line[]= "`$column->name` TEXT";
                break;
        }
    }
    $str = implode(",",$line);
    $sql = "CREATE TABLE IF NOT EXISTS `$tbl` ( $str );";
    if ($conn->query("$sql") === TRUE) {
        echo "Table $tbl successfully created'n";
    } else {
        echo "Error SQL: ".$conn->error ." >> $sql 'n";
        if ($die_on_mysql_error) {
            die;
        }
    }
    $table->close();
    // Import using dbf + fpt files (for MEMO data...)
    $fpt_file = str_replace( '.dbf', '.fpt', $db_path );
    $fpt_path = ( file_exists( $fpt_file ) ? $fpt_file : '' );
    import_dbf_to_mysql( $tbl, $db_path, $fpt_path );
//  import_dbf($db_path, $tbl);
}
function import_dbf($db_path, $tbl) {
    global $conn;
    global $die_on_mysql_error;
    // print_r ("$db_path'n");
    $table = new Table($db_path);
    print_r ("$table->recordCount'n");
    print_r (sizeof($table->columns));
    $i = 0;
    while ($record=$table->nextRecord()) {
        $fields = array();
        $line = array();
        foreach ($record->getColumns() as $column) {
            $fields[]=$column->name;
            // print_r("$column->name'n");
            switch($column->type) {
                case 'C':   // Character field
                case 'M':   // Memo type field
                    $line[]= sprintf("'%s'", $record->getObject($column) );
                    break;
                case 'F':   // Floating Point
                    $line[]=sprintf("%7.2f", $record->getObject($column) );
                    break;
                case 'N':   // Numeric
                    $line[]=sprintf("%d", $record->getObject($column) );
                    break;
                case 'L':   // Logical - ? Y y N n T t F f (? when not initialized).
                    // $line[] = sprintf("%d", ($record->getBoolean($column) ? 1 : 0) );
                    $line[] = sprintf("%d", $record->getString($column->name) );
                    break;
                case 'T':   // DateTime
                case 'D':   // Date
                    $line[]= sprintf("'%s'", strftime("%Y-%m-%d %H:%M", $record->getObject($column) ) );
                    break;
            }
        }
        $val = implode(",",$line);
        $col = implode(",",$fields);
        if($GLOBALS['from_encoding']!="")$val = mb_convert_encoding($val, 'UTF-8', $GLOBALS['from_encoding'] );
        $sql = "INSERT INTO `$tbl` ($col) VALUES ($val)'n";
        // print_r ("$sql");
        if ($conn->query("$sql") === TRUE) {
            $i++;
            if ( $i % 100 == 0 ) {
                echo "$i records inserted in $tbl'n";
            }
            die;
        } else {
            echo "Error SQL: ".$conn->error ." >> $sql 'n";
            if ($die_on_mysql_error) {
                die;
            }
        }
    }
    $table->close();
    echo "Table $tbl imported'n";
}
function import_dbf_to_mysql( $table, $dbf_path, $fpt_path ) {
    echo "Initializing import: Table $table'n";
    global $conn;
    global $die_on_mysql_error;
    $i = 0;
    $Test = new DBFhandler( $dbf_path, $fpt_path );
    while ( ($Record = $Test->GetNextRecord( true )) and ! empty( $Record ) ) {
        $a = 0;
        $sql1 = "INSERT INTO `$table` (";
        $sql2 = ") values (";
        $sql = "";
        foreach ( $Record as $key => $val ) {
            $key = (strpos($key, 0x00) !== false ) ? substr($key, 0, strpos($key, 0x00)) : $key;
            if ( $val == '{BINARY_PICTURE}' ) {
                continue;
            }
            $val = str_replace( "'", "", $val );
            if($GLOBALS['from_encoding']!="")$val = mb_convert_encoding($val, 'UTF-8', $GLOBALS['from_encoding'] );
            $a = $a + 1;
            if ( $a == 1 ) {
                $sql1 .="`$key`";
                $sql2 .="'" . trim( $val ) . "'";
            } else {
                $sql1 .=",`$key`";
                $sql2 .=",'$val'";
            }
        }
        $sql = "$sql1 $sql2)";
        if ($conn->query("$sql") === TRUE) {
            $i++;
            if ( $i % 100 == 0 ) {
                echo ".";
            }
        } else {
            echo "Error SQL: ".$conn->error ." >> $sql 'n";
            if ($die_on_mysql_error) {
                die;
            }
        }
  }
    echo "Table $table imported'n";
}