Question

我想更新我的数据，我使用它，但是它不会更新我的数据，import java.util.Random; import java.util.HashMap; // A common interface for all players interface Player { public void assignWeapon(String weapon); public void mission(); } // Terrorist must have weapon and mission class Terrorist implements Player { // Intrinsic Attribute private final String TASK; // Extrinsic Attribute private String weapon; public Terrorist() { TASK = "PLANT A BOMB"; } public void assignWeapon(String weapon) { // Assign a weapon this.weapon = weapon; } public void mission() { //Work on the Mission System.out.println("Terrorist with weapon " + weapon + "|" + " Task is " + TASK); } } // CounterTerrorist must have weapon and mission class CounterTerrorist implements Player { // Intrinsic Attribute private final String TASK; // Extrinsic Attribute private String weapon; public CounterTerrorist() { TASK = "DIFFUSE BOMB"; } public void assignWeapon(String weapon) { this.weapon = weapon; } public void mission() { System.out.println("Counter Terrorist with weapon " + weapon + "|" + " Task is " + TASK); } } // Claass used to get a playeer using HashMap (Returns // an existing player if a player of given type exists. // Else creates a new player and returns it. class PlayerFactory { /* HashMap stores the reference to the object of Terrorist(TS) or CounterTerrorist(CT). */ private static HashMap <String, Player> hm = new HashMap<String, Player>(); // Method to get a player public static Player getPlayer(String type) { Player p = null; /* If an object for TS or CT has already been created simply return its reference */ if (hm.containsKey(type)) p = hm.get(type); else { /* create an object of TS/CT */ switch(type) { case "Terrorist": System.out.println("Terrorist Created"); p = new Terrorist(); break; case "CounterTerrorist": System.out.println("Counter Terrorist Created"); p = new CounterTerrorist(); break; default : System.out.println("Unreachable code!"); } // Once created insert it into the HashMap hm.put(type, p); } return p; } } // Driver class public class CounterStrike { // All player types and weopons (used by getRandPlayerType() // and getRandWeapon() private static String[] playerType = {"Terrorist", "CounterTerrorist"}; private static String[] weapons = {"AK-47", "Maverick", "Gut Knife", "Desert Eagle"}; // Driver code public static void main(String args[]) { /* Assume that we have a total of 10 players in the game. */ for (int i = 0; i < 10; i++) { /* getPlayer() is called simply using the class name since the method is a static one */ Player p = PlayerFactory.getPlayer(getRandPlayerType()); /* Assign a weapon chosen randomly uniformly from the weapon array */ p.assignWeapon(getRandWeapon()); // Send this player on a mission p.mission(); } } // Utility methods to get a random player type and // weapon public static String getRandPlayerType() { Random r = new Random(); // Will return an integer between [0,2) int randInt = r.nextInt(playerType.length); // return the player stored at index 'randInt' return playerType[randInt]; } public static String getRandWeapon() { Random r = new Random(); // Will return an integer between [0,5) int randInt = r.nextInt(weapons.length); // Return the weapon stored at index 'randInt' return weapons[randInt]; } }仍然为空。那么，如何同时执行多个SQL查询呢？

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Answer 1

您可以在一个电话中用分号分隔发送多个SQL查询

$sql = "UPDATE laporan_gini SET id_provinsi='1' WHERE nama_item_vertical_variabel= 'INDONESIA';";
$sql.= "UPDATE laporan_gini SET id_provinsi='61' WHERE nama_item_vertical_variabel= 'KALIMANTAN BARAT';";

if (!$mysqli->multi_query($sql)) {
    echo "Multi query failed: (" . $mysqli->errno . ") " . $mysqli->error;
}

Answer 2

最好的方法是使用sql触发器或存储过程：
https://dev.mysql.com/doc/refman/8.0/en/trigger-syntax.html
https://dev.mysql.com/doc/connector-net/en/connector-net-tutorials-stored-procedures.html

以其他方式可以在代码中运行它：

<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

if (!$mysqli->query("DROP TABLE IF EXISTS test") || !$mysqli->query("CREATE TABLE test(id INT)")) {
    echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}

$sql = "SELECT COUNT(*) AS _num FROM test; ";
$sql.= "INSERT INTO test(id) VALUES (1); ";
$sql.= "SELECT COUNT(*) AS _num FROM test; ";

if (!$mysqli->multi_query($sql)) {
    echo "Multi query failed: (" . $mysqli->errno . ") " . $mysqli->error;
}

do {
    if ($res = $mysqli->store_result()) {
        var_dump($res->fetch_all(MYSQLI_ASSOC));
        $res->free();
    }
} while ($mysqli->more_results() && $mysqli->next_result());
?>

Answer 3

你永远不应该使用 mysqli::multi_query() 来执行你的 SQL，因为这个函数不支持参数绑定。您必须使用准备好的语句分别执行这两个查询。如果您不打算将任何数据绑定到您的 SQL，那么您可以将其减少一行并改用 mysqli::query()。

如果两个查询相互依赖，那么您可以将它们包装在一个事务中（假设您的表引擎支持事务）。

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("a", "a", "a", "a");
$mysqli->set_charset('utf8mb4'); // always set the charset

// start transaction
$mysqli->begin_transaction();

$sql = "UPDATE laporan_gini SET id_provinsi='1' WHERE nama_item_vertical_variabel= 'INDONESIA'";
$stmt = $mysqli->prepare($sql);
$stmt->execute();

$sql = "UPDATE laporan_gini SET id_provinsi='61' WHERE nama_item_vertical_variabel= 'KALIMANTAN BARAT'";
$stmt = $mysqli->prepare($sql);
$stmt->execute();

// commit data and end transaction
$mysqli->commit();

如何同时执行多个MySql查询？

3 个答案: