Question

我正在使用Java开发软件，我正在做的是在完整的sqlite数据库（55列和1000行）中搜索值并更新它。

我可以在数据库中找到该值，但是当我尝试更新它时，我想跳过只有NULL值的列。使用ResultSet它会自动跳过其他具有非空值的列。

如何检查ResultSet是否没有跳过列，找到所需的列并更新该值？

我尝试的是：

ArrayList<String> arr = new ArrayList<String>() ;
rs = statement.executeQuery(); // that is the select statement 
//Select * FROM table_name WHERE column1 like %VALUE%' OR column2 like %VALUE% and other columns like this too...
List<String> cols = Arrays.asList(getColLabels());
// I am getting Column Labels from ResultSetMetaData and it works fine  
while(rs.next()){
    for(String column: cols){
        String value;               
        if(rs.getBoolean(column)){      
    //That is the problematic area, if ResultSet finds a column with full of NULL values it skips to next column.
    // But other columns it skips too , which have not null Values and after that ResultSet does not find a proper column.

            if((value = rs.getObject(column).toString()).matches(".*"+searchedVal+".*") ){
        //searchedVal is searched value 
                arr.add("UPDATE Table_Name SET "+column+" ='"+newValue+"' WHERE "+ column+" ='" +value+"';"  );
                // then send array in another function to update to database
                break;
            }
        }
    }
}

感谢您的帮助。

Answer 1

请尝试使用数据层（SQL命令）解决problematic area，而不是业务线索（java代码）。

您想拥有所有列必须为非空的行吗？所以只需在sql命令中添加更多条件子句（not null）

类似的东西：

Select * FROM table_name WHERE column1 like %VALUE%' OR column2 like %VALUE% and column_n like %VALUE% and (column1 not null and column2 not null and column_n not null)

Answer 2

我找到了答案， rs.getBoolean不适用于不同类型的列类型，因此我更改了getObject函数。工作代码是：

ArrayList<String> arr = new ArrayList<String>() ;
rs = statement.executeQuery(); // that is the select statement 
//Select * FROM table_name WHERE column1 like %VALUE%' OR column2 like %VALUE% and other columns like this too...
List<String> cols = Arrays.asList(getColLabels());
// I am getting Column Labels from ResultSetMetaData and it works fine  
while(rs.next()){
    for(String column: cols){
        String value;               
        if(rs.getObject(column) != null){    

            if((value = rs.getObject(column).toString()).matches(".*"+searchedVal+".*") ){
        //searchedVal is searched value 
                arr.add("UPDATE Table_Name SET "+column+" ='"+newValue+"' WHERE "+ column+" ='" +value+"';"  );
                // then send array in another function to update to database
                break;
            }
        }
    }
}

Resultset跳过列

2 个答案: