Question

我的代码是

ContentValues values; 
values = new ContentValues();
        values.put(SQLHelper.EMPLOYEE_LPN, jsObj.getString("lpn"));
db.update(SQLHelper.EMPLOYEE_TABLE, values,
                "EMPLOYEE_LPN ='" + jsObj.getString("lpn") + "'",
                null);

Log Cat中显示警告

08-31 15:19:45.297: WARN/Database(2868): Reached MAX size for compiled-sql statement cache for database /data/data/org.sipdroid.sipua/databases/test.db; i.e., 
NO space for this sql statement in cache: 
SELECT EMPLOYEE_NAME FROM eyemployee WHERE EMPLOYEE_LPN ='1169162'. 
Please change your sql statements to use '?' for bindargs, instead of using actual values

如何解决？

Answer 1

查看示例8-3和8-4 here。

例8-3。使用更新方法

/**
 * Update a job in the database.
 * @param job_id         The job id of the existing job
 * @param employer_id    The employer offering the job
 * @param title          The job title
 * @param description    The job description
 */
public void editJob(long job_id, long employer_id, String title, String description) {
    ContentValues map = new ContentValues();
    map.put("employer_id", employer_id);
    map.put("title", title);
    map.put("description", description);
    String[] whereArgs = new String[]{Long.toString(job_id)};
    try{
        getWritableDatabase().update("jobs", map, "_id=?", whereArgs);
    } catch (SQLException e) {
        Log.e("Error writing new job", e.toString());
    }
}

以下是示例8-3中代码的一些要点：

示例8-4显示了如何使用execSQL方法 例8-4。使用execSQL方法

/**
 * Update a job in the database.
 * @param job_id         The job id of the existing job
 * @param employer_id    The employer offering the job
 * @param title          The job title
 * @param description    The job description
 */
public void editJob(long job_id, long employer_id, String title, String description) {
    String sql = 
        "UPDATE jobs " +
        "SET employer_id = ?, "+
        " title = ?,  "+
        " description = ? "+
        "WHERE _id = ? ";
    Object[] bindArgs = new Object[]{employer_id, title, description, job_id};
    try{
        getWritableDatabase().execSQL(sql, bindArgs);
    } catch (SQLException e) {
        Log.e("Error writing new job", e.toString());
    }
}

该消息要求您使参数使用sql变量而不是sql literals。

解析每个sql查询，生成计划并存储在sql语句缓存中。

从缓存中提取具有相同文本的查询。

  --One query
SELECT * FROM Customers WHERE Id = @1   (@1 = 3)
SELECT * FROM Customers WHERE Id = @1   (@1 = 4)
SELECT * FROM Customers WHERE Id = @1   (@1 = 5)

在缓存中找不到具有不同文本（包括文字）的查询，并且（无用地）添加了查询。

  --Three Queries.
SELECT * FROM Customers WHERE Id = 3
SELECT * FROM Customers WHERE Id = 4
SELECT * FROM Customers WHERE Id = 5

Answer 2

我今天正在寻找这个，并且遇到了这个文档。

http://ormlite.com/docs/query-builder

这解决了我的问题。这是上面链接中的代码

QueryBuilder<Account, String> queryBuilder =
  accountDao.queryBuilder();
Where<Account, String> where = queryBuilder.where();
SelectArg selectArg = new SelectArg();
// define our query as 'name = ?'
where.eq(Account.NAME_FIELD_NAME, selectArg);
// prepare it so it is ready for later query or iterator calls
PreparedQuery<Account> preparedQuery = queryBuilder.prepare();

// later we can set the select argument and issue the query
selectArg.setValue("foo");
List<Account> accounts = accountDao.query(preparedQuery);
// then we can set the select argument to another
// value and re-run the query
selectArg.setValue("bar");
accounts = accountDao.query(preparedQuery);

达到数据库的compile-sql语句高速缓存的MAX大小

2 个答案: