数据库的已编译SQL语句高速缓存达到的最大大小

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);

在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

怎么解决呢？

Answer 1

在这里查看示例8-3和8-4 。

示例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中的一些代码亮点：

例8-4显示了如何使用execSQL方法。
示例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文字。

解析每个sql查询，生成计划，并将其存储在sql语句缓存中。

从缓存中获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，并已（无用地）将查询添加到了该查询中。

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