Android的SQLite的默认值 [英] Android SQLite Default Value
本文介绍了Android的SQLite的默认值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想让用户输入一个字符串,说TEST,而定义表的列创建。
I want to make the user enter a String, say "TEST" while defining the columns of a table to be created.
让列名是标准
该用户永远不应该同时将行插入到所创建的表输入test了。
The user should never have to enter "TEST" again while inserting rows into the created Table.
所以将这个参数做的工作:
so will this parameter do the job :
创建表的表名(.....,标准文本默认的\\TEST \\');
create table tablename( ..... , standard text default \'TEST\');
请让我知道,因为我搜索了一会儿,不能让我的怀疑清零
Please let me know, as I searched a while and could not get my doubt cleared
推荐答案
为什么要使用 \\'\\'
在创建字符串?
Why do you use \' \'
in creation string?
以下工作:
private static final String CREATE_TABLE_CONTACT = CREATE_TABLE + CONTACT.TABLE_NAME + " (" + CONTACT._ID+ " INTEGER PRIMARY KEY," + CONTACT.FIRST_NAME + " TEXT, " + CONTACT.LAST_NAME + " TEXT DEFAULT 'TEST');";
下面是DBHelper的完整的例子:
Here is full example of DBHelper:
public class DBHelper extends SQLiteOpenHelper {
public static interface CONTACT extends BaseColumns {
String TABLE_NAME = "human";
String FIRST_NAME = "first_name";
String LAST_NAME = "last_name";
}
private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS ";
private static final String DATABASE_NAME = "someDataBase";
private static final int DATABASE_VERSION = 1;
private static final String CREATE_TABLE_CONTACT = CREATE_TABLE + CONTACT.TABLE_NAME + " (" + CONTACT._ID
+ " INTEGER PRIMARY KEY," + CONTACT.FIRST_NAME + " TEXT, " + CONTACT.LAST_NAME
+ " TEXT DEFAULT 'TTEESSTT');";
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE_CONTACT);
}
@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
db.execSQL("DROP TABLE IF EXISTS " + CONTACT.TABLE_NAME);
onCreate(db);
}
public Cursor getAllContacts() {
return getReadableDatabase().query(CONTACT.TABLE_NAME, null, null, null, null, null, null);
}
//method to insert contact
public void insertContact(String firstName, String lastName) {
final ContentValues values = new ContentValues();
values.put(CONTACT.FIRST_NAME, firstName);
//optional parameter
if (lastName != null) {
values.put(CONTACT.LAST_NAME, lastName);
}
getWritableDatabase().insert(CONTACT.TABLE_NAME, null, values);
}
}
And its usage, for example:
DBHelper db = new DBHelper(this);
db.insertContact("Dmitry", "Antonov");
db.insertContact("Andy", "Sudorov");
db.insertContact("Oleg", null);
db.insertContact("Ivan", "Lozin");
db.insertContact("Serg", null);
Cursor allContacts = db.getAllContacts();
ListView testList = (ListView) findViewById(R.id.testList);
testList.setAdapter(new SimpleCursorAdapter(this, android.R.layout.two_line_list_item, allContacts,
new String[] { DBHelper.CONTACT.FIRST_NAME, DBHelper.CONTACT.LAST_NAME }, new int[] {android.R.id.text1, android.R.id.te
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