在SQLite中获取列的类型

Question

我的队友为我的Android应用程序制作了数据库.例如,其中一个表是这样创建的:

CREATE TABLE table1(
    id_fields_starring INTEGER PRIMARY KEY AUTOINCREMENT
    , fields_descriptor_id INTEGER NOT NULL
    , starring_id INTEGER NOT NULL
    , form_mandatory INTEGER NOT NULL DEFAULT 1
    , form_visible INTEGER NOT NULL DEFAULT 1
    , FOREIGN KEY(fields_descriptor_id) REFERENCES pr_fields_descriptor(id_fields_descriptor) ON DELETE CASCADE ON UPDATE CASCADE
    , FOREIGN KEY(starring_id) REFERENCES starring(id_starring) ON DELETE CASCADE ON UPDATE CASCADE
)

从表中的字段,我需要知道其中哪些是INTEGER NOT NULL和是INTEGER NOT NULL DEFAULT 1,因为第一种情况下,我必须dinamically的创建EditText和第二种情况下我必须创建一个CheckBox.任何的想法？

Answer 1

呼叫:

PRAGMA table_info(table1);

将转储表信息,例如

cid|name                 |type    |notnull |dflt_value |pk
0  |id_fields_starring   |INTEGER |0       |           |1
1  |fields_descriptor_id |INTEGER |1       |           |0
2  |starring_id          |INTEGER |1       |           |0
3  |form_mandatory       |INTEGER |1       |1          |0
4  |form_visible         |INTEGER |1       |1          |0

并简单地用notnull=1和找到光标中的行dflt_value=1

编辑:

要列出定义的所有列,INTEGER NOT NULL DEFAULT 1这将是有效的(helper是您的实例SQLiteOpenHelper):

SQLiteDatabase db = helper.getWritableDatabase();
Cursor cursor = db.rawQuery("PRAGMA table_info(table1)", null);
try {
    int nameIdx = cursor.getColumnIndexOrThrow("name");
    int typeIdx = cursor.getColumnIndexOrThrow("type");
    int notNullIdx = cursor.getColumnIndexOrThrow("notnull");
    int dfltValueIdx = cursor.getColumnIndexOrThrow("dflt_value");
    ArrayList<String> integerDefault1NotNull = new ArrayList<String>();
    while (cursor.moveToNext()) {
        String type = cursor.getString(typeIdx);
        if ("INTEGER".equals(type)) {
            // Integer column
            if (cursor.getInt(notNullIdx) == 1) {
                // NOT NULL
                String defaultValue = cursor.getString(dfltValueIdx);
                if ("1".equals(defaultValue)) {
                    integerDefault1NotNull.add(cursor.getString(nameIdx));
                }
            }
        }
    }
    System.out.println("integerDefault1NotNull now contains a list of all columns " +
            " defined as INTEGER NOT NULL DEFAULT 1, " + integerDefault1NotNull);
} finally {
    cursor.close();
}