PreparedStatement:我可以提供列名作为参数吗? [英] PreparedStatement: Can I supply the column name as parameter?

问题描述

假设我有一个包含3列的表格:C1，C2，C3

Let's say I have a table with 3 columns: C1, C2, C3

我根据C1列进行搜索. 我可以做类似这样的事情吗( 这不起作用 -因为这不是 prepareStatement的使用方式:))

I make a search based on the C1 column. Could I make something similar like this (this is not working - because this is not the way prepareStatement it's used:) )

String c;// the name of the column

...    
String sql = "select * from table where ?  = ?";
                pre = con.prepareStatement(sql);
                pre.setString(1, c);
                pre.setString(1, i);
                rs = pre.executeQuery();

主要思想是，我不想每列都有3个ifs.一个优雅的解决方案?

The main idea, I don't want to have 3 ifs for every column. An elegant solution?

推荐答案

您可以编写一组sql查询并将其存储在地图中，然后根据相关列获取一个.

you could code up a a set of sql queries and store them in a map, then grab one based on the column in question.

enum column { a, b, c}

Map<column, string> str;

static {
 str.put(a, "select * from tbl where a = ? ");
 ...
}

然后根据枚举从地图中抢一张. sql语句中的字符串追加有可能在将来成为安全问题.

then just grab one out of the map later based on the enum. String appends in sql statements have a way of becoming security problems in the future.

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