增加的android / SQLite数据库记录的值 [英] Increase the value of a record in android/sqlite database
问题描述
我试着在我的表增加一列整数键的值。然而,没有什么似乎发生。
I try to increase the value of an integer key in a row in my table. However, nothing really seems to happen.
db.rawQuery("UPDATE table SET key = key + 1 WHERE name=?", new String[] {name});
然而,这code正常工作(只是设置的关键硬codeD值):
However, this code works fine (just sets the key to a hard-coded value):
ContentValues values = new ContentValues();
values.put("key", 2);
db.update("table", values, "name=?", new String[] {name});
也试过'?而不是只?,但它只是导致在运行时错误。
Also tried '?' instead of just ?, but it resulted just in a run-time error.
推荐答案
从的http://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html:
公开光标rawQuery(SQL字符串,字符串[] selectionArgs两个)
public Cursor rawQuery (String sql, String[] selectionArgs)
运行提供的SQL和返回游标在结果集。返回一个光标对象,它位于第一条目之前
Runs the provided SQL and returns a Cursor over the result set. Returns a Cursor object, which is positioned before the first entry
比的
公共无效execSQL(SQL字符串,对象[] bindArgs)
public void execSQL (String sql, Object[] bindArgs)
执行一个SQL语句不是一个查询。例如, CREATE TABLE
,删除
,插入
等
Execute a single SQL statement that is not a query. For example, CREATE TABLE
, DELETE
, INSERT
, etc.
在换句话说,SQL查询这些数据将与 rawQuery
运行返回表,而那些不回表要与 execSQL
。
In other words, SQL queries which return a table are to be run with rawQuery
, and those that do not return tables are to be run with execSQL
.
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