Android 创建 table 时出现 SQLite 错误（VARCHAR 导致错误）

Question

import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

SQLiteDatabase db;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    db = this.openOrCreateDatabase("Practice", MODE_PRIVATE, null);

    db.execSQL("CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR, notes VARCHAR, amount VARCHAR");
}

错误日志：

E/SQLiteLog: (1) near "VARCHAR": syntax error 06-30 23:46:21.834 11420-11420/com.asd.sqltesting D/AndroidRuntime: Shutting down VM 06-30 23:46:21.835 11420-11420/com.asd.sqltesting E/AndroidRuntime: FATAL EXCEPTION: main Process: com.asd.sqltesting, PID: 11420 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.asd.sqltesting/com.asd.sqltesting.MainActivity}: android.database.sqlite.SQLiteException: near "VARCHAR": syntax error (code 1): , while compiling: CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR, notes VARCHAR, amount VARCHAR at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360) at android.app.ActivityThread.access0(ActivityThread.java:144) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) Caused by: android.database.sqlite.SQLiteException: near "VARCHAR": syntax error (code 1): , while compiling: CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR, notes VARCHAR, amount VARCHAR at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method) at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889) at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500) at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588) at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:58) at android.database.sqlite.SQLiteStatement.(SQLiteStatement.java:31) at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1674) at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1605) at com.asd.sqltesting.MainActivity.onCreate(MainActivity.java:18) at android.app.Activity.performCreate(Activity.java:5933) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360) at android.app.ActivityThread.access0(ActivityThread.java:144) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

我试图创建一个包含多个列的 table，但这种情况一直在发生。这行代码用于另一个项目，但我第二次在同一个 activity 中使用它时出现错误。

Answer 1

你错过了结尾')'：

db.execSQL("CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR, notes VARCHAR, amount VARCHAR);");

VARCHAR 的大小在 sqlite 中是可选的

参见 https://www.sqlite.org/syntax/type-name.html。

要验证您的陈述，您可以使用 sqlite3

$ sqlite3 
SQLite version 3.8.10.2 2015-05-20 18:17:19
Enter ".help" for usage hints.
Connected to a transient in-memory database.
sqlite> CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR, notes VARCHAR, amount VARCHAR);

Answer 2

您缺少圆括号。

这样写您的查询：

db.execSQL("CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR, notes VARCHAR, amount VARCHAR)");

Insert a ) after amount VARCHAR

编辑：1

android.database.sqlite.SQLiteException : (1) near "VARCHAR": syntax error

Your logcat is displaying this Exception. So generally this exception arises whenever you are missing some character like , or " or in your case it is ). Observe your query you will find two opening round brackets (, One before Create table & 2nd after blah. But there is only one closing bracket ) at the end. This is the reason i have suggested you to add one ) after amount VARCHAR.

Answer 3

您的查询有误，您漏掉了结束符 ')': 不要直接在 MainActivity 中创建数据库，遵循以下方法并始终通过异步任务调用数据库，

使用 SQLiteOpenHelper 的最佳实践，参考下面的 bolg

https://github.com/codepath/android_guides/wiki/Local-Databases-with-SQLiteOpenHelper

示例项目

创建 table 如下所示，

样本：

String CREATE_POSTS_TABLE = "CREATE TABLE " + TABLE_POSTS +
            "(" +
                KEY_POST_ID + " INTEGER PRIMARY KEY," + // Define a primary key
                KEY_POST_USER_ID_FK + " INTEGER REFERENCES " + TABLE_USERS + "," + // Define a foreign key
                KEY_POST_TEXT + " TEXT" +
            ")";

String CREATE_USERS_TABLE = "CREATE TABLE " + TABLE_USERS +
        "(" +
            KEY_USER_ID + " INTEGER PRIMARY KEY," +
            KEY_USER_NAME + " TEXT," +
            KEY_USER_PROFILE_PICTURE_URL + " TEXT" +
        ")";

db.execSQL(CREATE_POSTS_TABLE);
db.execSQL(CREATE_USERS_TABLE);

Answer 4

sql查询错误。

先更正一下

db.execSQL("CREATE TABLE IF NOT EXISTS blah (subjects VARCHAR(size), notes VARCHAR(size), amount VARCHAR(size))");

Android 创建 table 时出现 SQLite 错误（VARCHAR 导致错误）

Android SQLite error when creating a table (VARCHAR is causing an error)

java

android

sqlite

varchar