使用 Flutter 插入 sqflite 时出现问题

Question

我在 Flutter 中遇到 sqflite 问题。 正常插入工作得很好......但是一旦我插入一个值，即 id 我从将 int 插入第一个表中得到，我在“）”附近得到一个语法错误。

这是我得到的错误：

flutter: 错误 DatabaseException(Error Domain=FMDatabase Code=1 "near ")": 语法错误" UserInfo={NSLocalizedDescription=near ")": 语法 错误}) sql 'CREATE TABLE pageM (id INTEGER PRIMARY KEY,caardId INTEGER,title INTEGER,content TEXT,)' args []} 在​​打开、关闭... [VERBOSE-2:ui_dart_state.cc(157)] 未处理的异常： DatabaseException（错误域=FMDatabase 代码=1“近”）：语法 error" UserInfo={NSLocalizedDescription=near ")": 语法错误}) sql 'CREATE TABLE pageM (id INTEGER PRIMARY KEY,caardId INTEGER,title 整数，内容文本，)' args []} #0 wrapDatabaseException (package:sqflite/src/exception_impl.dart:11:7) #1 SqfliteDatabaseFactoryImpl.wrapDatabaseException（包：sqflite/src/factory_impl.dart:78:7） #2 SqfliteDatabaseMixin.safeInvokeMethod（包：sqflite_common/src/database_mixin.dart:208:15） #3 SqfliteDatabaseMixin.invokeExecute (package:sqflite_common/src/database_mixin.dart:370:12) #4 SqfliteDatabaseMixin.txn 执行。 （包：sqflite_common/src/database_mixin.dart:362:14） #5 SqfliteDatabaseMixin.txnSynchronized (package:sqflite_common/src/database_mixin.dart:312:26) #6 SqfliteDatabaseMixin.txnWriteSynchronized (包:sqflite_common/src/database_mixin.dart:345:

这是我的插入：

onPressed: () async {
    currentCaard = Caard(topicId: widget.topicId, pageAmount: widget.pageAmount);
    print(currentCaard);
    currentCaard.id = await DatabaseProviderCaard.db.insert(currentCaard);
    currentPage = PageM(caardId: currentCaard.id, title: textControllerTitle.text,content: textControllerContent.text);
    DatabaseProviderPage.db.insert(currentPage);
},

这是我的整个 db Provider 文件：

import 'package:caards/model.dart';
import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';
import 'package:sqflite/sqlite_api.dart';

class DatabaseProviderCaard {
  static const String TABLE_CAARD = "caard";
  static const String COLUMN_ID = "id";
  static const String COLUMN_TOPIC_ID = "topicId";
  static const String COLUMN_PAGE_AMOUNT = "pageAmount";

  DatabaseProviderCaard._();
  static final DatabaseProviderCaard db = DatabaseProviderCaard._();

  Database _database;

  Future<Database> get database async {
    print("caard database getter called");

    if (_database != null) {
      return _database;
    }

    _database = await createDatabase();

    return _database;
  }

  Future<Database> createDatabase() async {
    String dbPath = await getDatabasesPath();

    return await openDatabase(
        join(dbPath, 'caardDB.db'),
        version: 1,
        onCreate: (Database  database, int version) async {
        print("Creating caard table");

        await database.execute(
          "CREATE TABLE $TABLE_CAARD ("
              "$COLUMN_ID INTEGER PRIMARY KEY,"
              "$COLUMN_TOPIC_ID INTEGER,"
              "$COLUMN_PAGE_AMOUNT INTEGER"
              ")",
          );
        },
    );
  }

  Future<List<Caard>> getCaards() async {
    final db = await database;

    var caards = await db
        .query(TABLE_CAARD, columns: [COLUMN_ID, COLUMN_TOPIC_ID, COLUMN_PAGE_AMOUNT]);

    List<Caard> caardList = List<Caard>();

    caards.forEach((currentCaard) {
      Caard caard = Caard.fromMap(currentCaard);

      caardList.add(caard);
    });

    return caardList;
  }

  Future<int> insert(Caard caard) async {
    final db = await database;
    caard.id = await db.insert(TABLE_CAARD, caard.toMap());
    return caard.id;
  }

  Future<int> delete(int id) async {
    final db = await database;

    return await db.delete(
      TABLE_CAARD,
      where: "id = ?",
      whereArgs: [id],
    );
  }

  Future<int> update(Caard caard) async {
    final db = await database;

    return await db.update(
      TABLE_CAARD,
      caard.toMap(),
      where: "id = ?",
      whereArgs: [caard.id],
    );
  }
}


class DatabaseProviderPage {
  static const String TABLE_PAGE = "page";
  static const String COLUMN_ID = "id";
  static const String COLUMN_CAARD_ID = "caardId";
  static const String COLUMN_TITLE = "title";
  static const String COLUMN_CONTENT = "content";


  DatabaseProviderPage._();
  static final DatabaseProviderPage db = DatabaseProviderPage._();

  Database _database;

  Future<Database> get database async {
    print("page database getter called");

    if (_database != null) {
      return _database;
    }

    _database = await createDatabase();

    return _database;
  }

  Future<Database> createDatabase() async {
    String dbPath = await getDatabasesPath();

    return await openDatabase(
      join(dbPath, 'pageDB.db'),
      version: 1,
      onCreate: (Database  database, int version) async {
        print("Creating page table");

        await database.execute(
          "CREATE TABLE $TABLE_PAGE ("
              "$COLUMN_ID INTEGER PRIMARY KEY,"
              "$COLUMN_CAARD_ID INTEGER,"
              "$COLUMN_TITLE INTEGER,"
              "$COLUMN_CONTENT TEXT,"
              ")",
        );
      },
    );
  }

  Future<List<PageM>> getPages() async {
    final db = await database;

    var pages = await db
        .query(TABLE_PAGE, columns: [COLUMN_ID, COLUMN_CAARD_ID, COLUMN_TITLE, COLUMN_CONTENT]);

    List<PageM> pageList = List<PageM>();

    pages.forEach((currentPage) {
      PageM page = PageM.fromMap(currentPage);

      pageList.add(page);
    });

    return pageList;
  }

  Future<PageM> insert(PageM pageM) async {
    final db = await database;
    pageM.id = await db.insert(TABLE_PAGE, pageM.toMap());
    return pageM;
  }

  Future<int> delete(int id) async {
    final db = await database;

    return await db.delete(
      TABLE_PAGE,
      where: "id = ?",
      whereArgs: [id],
    );
  }

  Future<int> update(PageM page) async {
    final db = await database;

    return await db.update(
      TABLE_PAGE,
      page.toMap(),
      where: "id = ?",
      whereArgs: [page.id],
    );
  }
}

这是我的模型：

import 'package:caards/database_provider.dart';

class Caard {
  int id;
  int topicId;
  int pageAmount;

  Caard({this.id, this.topicId, this.pageAmount});

  Map<String, dynamic> toMap() {
    var map = <String, dynamic>{
      DatabaseProviderCaard.COLUMN_ID: id,            //versuch
      DatabaseProviderCaard.COLUMN_TOPIC_ID: topicId,
      DatabaseProviderCaard.COLUMN_PAGE_AMOUNT: pageAmount
    };
    
    if (id != null) {
      map[DatabaseProviderCaard.COLUMN_ID] = id;
    }
    
    return map;
  }
  
  Caard.fromMap(Map<String, dynamic> map) {
    id = map[DatabaseProviderCaard.COLUMN_ID];
    topicId = map[DatabaseProviderCaard.COLUMN_TOPIC_ID];
    pageAmount = map[DatabaseProviderCaard.COLUMN_PAGE_AMOUNT];
  }
}



class PageM {
  int id;
  int caardId;
  String title;
  String content;

  PageM({this.id, this.caardId, this.title, this.content});

  Map<String, dynamic> toMap() {
    var map = <String, dynamic>{
      DatabaseProviderPage.COLUMN_CAARD_ID: caardId, 
      DatabaseProviderPage.COLUMN_TITLE: title,
      DatabaseProviderPage.COLUMN_CONTENT: content
    };

    if (id != null) {
      map[DatabaseProviderPage.COLUMN_ID] = id;
    }

    return map;
  }

  PageM.fromMap(Map<String, dynamic> map) {
    id = map[DatabaseProviderPage.COLUMN_ID];
    caardId = map[DatabaseProviderPage.COLUMN_CAARD_ID];
    title = map[DatabaseProviderPage.COLUMN_TITLE];
    content = map[DatabaseProviderPage.COLUMN_CONTENT];
  }
}

```

Answer 1

您需要在语法上更正 SQL 查询。 您目前使用：

'CREATE TABLE pageM (id INTEGER PRIMARY KEY,caardId INTEGER,title INTEGER,content TEXT,)'

此查询末尾有一个额外的逗号，这在语法上不正确。这就是数据库抱怨语法错误的原因。事实上，在 DB 的错误消息中，有使用代码创建的查询，其中括号前有一个尾随逗号“，”。更改您的代码，以便查询是：

 'CREATE TABLE pageM (id INTEGER PRIMARY KEY,caardId INTEGER,title INTEGER,content TEXT)'

您需要更改 DB Provider 文件中的以下部分。 错误是因为下面部分TEXT后面有个逗号：

 await database.execute(
          "CREATE TABLE $TABLE_PAGE ("
              "$COLUMN_ID INTEGER PRIMARY KEY,"
              "$COLUMN_CAARD_ID INTEGER,"
              "$COLUMN_TITLE INTEGER,"
              "$COLUMN_CONTENT TEXT,"
              ")",

正确的版本如下。

await database.execute(
          "CREATE TABLE $TABLE_PAGE ("
              "$COLUMN_ID INTEGER PRIMARY KEY,"
              "$COLUMN_CAARD_ID INTEGER,"
              "$COLUMN_TITLE INTEGER,"
              "$COLUMN_CONTENT TEXT"
              ")",