使用 Flutter 插入 sqflite 时出现问题
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【中文标题】使用 Flutter 插入 sqflite 时出现问题【英文标题】:Problem inserting into sqflite using Flutter 【发布时间】:2020-11-10 17:01:39 【问题描述】: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];
```
【问题讨论】:
【参考方案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"
")",
【讨论】:
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