String sql = "update actor set actor_name=? where id=?";
时间: 2024-05-19 19:14:26 浏览: 7
This is a SQL statement that updates the name of an actor in a database table called "actor". The statement uses two placeholders indicated by the question marks:
1. The first placeholder is for the new name of the actor and will be replaced with a value when the statement is executed.
2. The second placeholder is for the ID of the actor whose name will be updated and will also be replaced with a value when the statement is executed.
The statement is dynamic because it can be used to update any actor's name by passing in the appropriate values for the placeholders.
相关问题
public List<Movie> getPageData(int startindex, int pagesize, String category_id){ try { QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); String sql = "select * from movie where category_id=? limit ?,?"; Object params[] = {category_id, startindex, pagesize}; return (List<Movie>)runner.query(sql, params, new BeanListHandler(Movie.class)); } catch (Exception e) { e.printStackTrace(); throw new RuntimeException(e); } } public int getTotalRecord(String category_id){ try { QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); String sql = "select count(*) from movie where category_id=?"; long totalrecord = (Long)runner.query(sql, category_id, new ScalarHandler()); return (int)totalrecord; } catch (Exception e) { e.printStackTrace(); throw new RuntimeException(e); } } //(id,name,author,price,image,description,category_id) @Override public void update(Movie movie) { try { QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); String sql = "update movie set name=?,actor=?,price=?,poster=?,intro=?,category_id=? where id=?"; Object params[] = { movie.getName(), movie.getActor(), movie.getPrice(), movie.getPoster(), movie.getIntro(), movie.getCategory_id(),movie.getId()}; runner.update(sql, params); } catch (SQLException e) { e.printStackTrace(); throw new RuntimeException(e); } } @Override public int delete(String id) { try { QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); //执行删除的sql runner.update("delete from movie where id=?",id); } catch (SQLException e) { throw new RuntimeException(e);//抛出运行异常 } return 1;//删除成功返回1表示结束 }帮我加一下注释
好的,以下是代码的注释:
```
// 获取指定类别下的电影列表(分页)
public List<Movie> getPageData(int startindex, int pagesize, String category_id){
try {
QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); // 获取数据库连接
String sql = "select * from movie where category_id=? limit ?,?"; // 查询语句
Object params[] = {category_id, startindex, pagesize}; // 查询参数
return (List<Movie>)runner.query(sql, params, new BeanListHandler(Movie.class)); // 执行查询并返回结果
} catch (Exception e) {
e.printStackTrace(); // 打印异常信息
throw new RuntimeException(e); // 抛出运行时异常
}
}
// 获取指定类别下的电影总数
public int getTotalRecord(String category_id){
try {
QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); // 获取数据库连接
String sql = "select count(*) from movie where category_id=?"; // 查询语句
long totalrecord = (Long)runner.query(sql, category_id, new ScalarHandler()); // 执行查询并返回结果
return (int)totalrecord; // 将结果转换为整型并返回
} catch (Exception e) {
e.printStackTrace(); // 打印异常信息
throw new RuntimeException(e); // 抛出运行时异常
}
}
// 更新电影信息
@Override
public void update(Movie movie) {
try {
QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); // 获取数据库连接
String sql = "update movie set name=?,actor=?,price=?,poster=?,intro=?,category_id=? where id=?"; // 更新语句
Object params[] = { movie.getName(), movie.getActor(), movie.getPrice(), movie.getPoster(), movie.getIntro(), movie.getCategory_id(),movie.getId()}; // 更新参数
runner.update(sql, params); // 执行更新操作
} catch (SQLException e) {
e.printStackTrace(); // 打印异常信息
throw new RuntimeException(e); // 抛出运行时异常
}
}
// 删除电影信息
@Override
public int delete(String id) {
try {
QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); // 获取数据库连接
//执行删除的sql语句
runner.update("delete from movie where id=?",id); // 删除操作
} catch (SQLException e) {
throw new RuntimeException(e); // 抛出运行时异常
}
return 1; // 删除成功返回1表示结束
}
```
for actor_comb, info in sorted(actor_comb_dict.items(), key=lambda x: (-x[1][0], pinyin(x[0]))): if len(actor_comb) == 3: actor_comb_str = ','.join(actor_comb) ws2.cell(row=row_num, column=1).value = actor_comb_str ws2.cell(row=row_num, column=2).value = info[0] ws2.cell(row=row_num, column=3).value = ','.join(info[1]) row_num += 1 # 写入二人组合 for actor_comb, info in sorted(actor_comb_dict.items(), key=lambda x: (-x[1][0], pinyin(x[0]))): if len(actor_comb) == 2: actor_comb_str = ','.join(actor_comb) is_covered = False for three_actor_comb in actor_comb_dict: if len(three_actor_comb) == 3 and set(actor_comb).issubset(set(three_actor_comb)): is_covered = True break if not is_covered: ws2.cell(row=row_num, column=1).value = actor_comb_str ws2.cell(row=row_num, column=2).value = info[0] ws2.cell(row=row_num, column=3).value = ','.join(info[1]) row_num += 1 wb.save('D:\\pythonProject1\\电影信息统计.xlsx') wb.close() actor_combination_statistics()请详细地解释上述代码
这段代码是一个函数,函数名为actor_combination_statistics()。该函数实现了对电影演员组合的统计和排名,并将结果写入一个Excel文件中。
具体来说,该函数首先定义了一个字典actor_comb_dict,用于存储每个演员组合的出现次数和参演电影列表。接着,函数通过遍历电影列表,对每个电影的演员组合进行统计,更新actor_comb_dict中的数据。
随后,函数通过两个循环分别对三人组合和二人组合进行排序和筛选。排序时,按照出现次数和拼音顺序进行排序。筛选时,对于一个二人组合,只有当它没有被任何一个三人组合包含时才会被计入结果。最后,函数将结果写入Excel文件中。
总之,这段代码实现了一个简单的电影演员组合统计功能,通过Excel表格的形式展示了不同组合的出现次数和相关信息。