SQLite 编译时出错:如果不存在则创建表条目(文本主键、测试文本、)

Question

这是我第一次尝试使用SQLite，我收到了一个常见的冲突，但是，我无法自己解决它。以下是问题的原因。

03-10 17:43:21.747: E/AndroidRuntime(11225): Caused by: android.database.sqlite.SQLiteException: near ")": syntax error (code 1): , while compiling: CREATE TABLE IF NOT EXISTS entry ( TEXT PRIMARY KEY, Test TEXT, )

我知道这种方法以某种方式构造不正确，但我需要帮助弄清楚如何。

private void createEntryTable(SQLiteDatabase db) {
    StringBuilder entryTableFields = new StringBuilder();
    entryTableFields.append(EntryTable.Cols.COLUMN_ENTRY)
    .append(" TEXT PRIMARY KEY, ")
    .append(EntryTable.Cols.COLUMN_TEST).append(" TEXT, ");
    createTable(db, EntryTable.TABLE_NAME, entryTableFields.toString());
}

以下是我设置SQLite的方式。首先，我的表只有两列。

public class EntryTable {
    public static final String TABLE_NAME = "entry";
    public static final String PATH = "entry";
    public static final int PATH_TOKEN = 2015;
    public static final Uri CONTENT_URI = ContentDescriptor.BASE_URI.buildUpon().appendPath(PATH).build();
    public static class Cols {
        // Table column names
        public static final String COLUMN_ENTRY = "Entry";
        public static final String COLUMN_TEST = "Test";
    }
}

我创建了一个 ContentDescriptor 类。

public class ContentDescriptor {
    public static final String AUTHORITY = "com.package";
    public static final Uri BASE_URI = Uri.parse("content://" + AUTHORITY);
    public static final UriMatcher URI_MATCHER = buildUriMatcher();
    private static UriMatcher buildUriMatcher() {
        final UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
        // add as many tables as you want below
        matcher.addURI(AUTHORITY, EntryTable.PATH, EntryTable.PATH_TOKEN);
        return matcher;
    }
}

我有一个数据库管理器类

public class DatabaseManager {
    public static void saveEntry(Context context, String entry) {
        try {
            ContentValues values = getContentValuesEntryTable(entry);
            ContentResolver resolver = context.getContentResolver();
            Cursor cursor = resolver.query(EntryTable.CONTENT_URI, null, null, null, null);
            if (cursor != null && cursor.getCount() > 0) {
                resolver.update(EntryTable.CONTENT_URI, values, null, null);
            } else {
                resolver.insert(EntryTable.CONTENT_URI, values);
            }
            cursor.close();
            resolver.insert(EntryTable.CONTENT_URI, values);
        } catch (Exception e) {
            Log.e("TEST", "error: " + e.toString());
            e.printStackTrace();
        }
    }
    public static Cursor getEntry(Context context, String entry) {
        Cursor cursor;
        String sorting = null;
        if (TextUtils.isEmpty(entry)) {
            cursor = context.getContentResolver().query(EntryTable.CONTENT_URI, null, null, null, sorting);
        } else {
            cursor = context.getContentResolver().query(EntryTable.CONTENT_URI, null, EntryTable.Cols.COLUMN_ENTRY + " = '" + entry + "'", null, sorting);
        }
        if (cursor != null) {
            cursor.moveToFirst();
        }
        return cursor;
    }
    private static ContentValues getContentValuesEntryTable(String entry) {
        ContentValues values = new ContentValues();
        values.put(EntryTable.Cols.COLUMN_ENTRY, entry);
        return values;
    }
}

最后我有一个DBHelper类

public class DatabaseHelper extends SQLiteOpenHelper {
    public static final String KEY_CREATE_TABLE = "CREATE TABLE IF NOT EXISTS {0} ({1})";
    public static final String KEY_DROP_TABLE = "DROP TABLE IF EXISTS {0}";
    private static final int CURRENT_DB_VERSION = 1;
    private static final String DB_NAME = "qmun.db";
    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, CURRENT_DB_VERSION);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        Log.d("TEST", "DB Creation :: Going to create db ");
        createEntryTable(db);
    }
    private void createEntryTable(SQLiteDatabase db) {
        StringBuilder entryTableFields = new StringBuilder();
        entryTableFields.append(EntryTable.Cols.COLUMN_ENTRY)
        .append(" TEXT PRIMARY KEY, ")
        .append(EntryTable.Cols.COLUMN_TEST).append(" TEXT, ");
        createTable(db, EntryTable.TABLE_NAME, entryTableFields.toString());
    }
    public void dropTable(SQLiteDatabase db, String name) {
        String query = MessageFormat.format(DatabaseHelper.KEY_DROP_TABLE, name);
        db.execSQL(query);
    }
    public void createTable(SQLiteDatabase db, String name, String fields) {
        String query = MessageFormat.format(DatabaseHelper.KEY_CREATE_TABLE, name, fields);
        db.execSQL(query);
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        dropTable(db, EntryTable.TABLE_NAME);
        onCreate(db);
    }
}

从我的主活动中，我正在尝试插入数据

DatabaseManager.saveEntry(MainActivity.this, "text goes into my db");

提前感谢您的帮助。我正在慢慢理解SQLite。

Answer 1

答案在你的标题中。

问题在于 CREATE 命令末尾的小"，"：

如果不存在，则创建表条目（文本主键、测试文本**，**）

SQLite 明确不喜欢右括号前的逗号。

我想，当您完成命令时，您可以解决此问题 - 例如，在字段中任何尾随逗号的 createTable 条中。

当然，在这里删除它会更简单

    .append(EntryTable.Cols.COLUMN_TEST).append(" TEXT, ");

只是，当您也想将 createTable 用于其他表时，可能值得考虑一个通用解决方案，其中调用者不需要考虑逗号......

Answer 2

( TEXT PRIMARY KEY, Test TEXT, )

看起来你这里有一个额外的逗号？

（摘自下面的日志）

Caused by: android.database.sqlite.SQLiteException: near ")": syntax error (code 1): , while compiling: CREATE TABLE IF NOT EXISTS entry ( TEXT PRIMARY KEY, Test TEXT, )