jdbc reading resultSet by colName issue for aliases - scala

Question

I have a generic repository with a method as:
object Queries {
def getByFieldId(field: String, id: Int): String = {
s"""
|SELECT
| DF.id AS fileId,
| DF.name AS fileName,
| AG.id AS groupId,
| AG.name AS groupName
|FROM $tableName DFG
|INNER JOIN directory_files DF on DF.id = DFG.file_id
|INNER JOIN ad_groups AG on AG.id = DFG.group_id
|WHERE DFG.$field = $id
|""".stripMargin
}
}
def getByFieldId(field: String, id: Int): Try[List[Object]] = {
try {
val sqlQuery = Queries.getByFieldId("ad_group", 1)
statement = conn.getPreparedStatement(sqlQuery)
setParameters(statement, params)
resultSet = statement.executeQuery()
val metadata = resultSet.getMetaData
val columnCount = metadata.getColumnCount
val columns: ListBuffer[String] = ListBuffer.empty
for (i <- 1 to columnCount) {
columns += metadata.getColumnName(i)
}
var item: List[Object] = List.empty
while (resultSet.next()) {
val row = columns.toList.map(x => resultSet.getObject(x))
item = row
}
Success(item)
} catch {
case e: Any => Failure(errorHandler(e))
} finally conn.closeConnection(resultSet, statement)
}
The problems is that my result set ignore the query aliases and return columns as (id, name, id, name) instead of (fileId, fileName, groupId, groupName).
One solution found is to use column index instead of col names, but I'm not sure if this solution will cover entire app and will not break some other queries.
Maybe, another found solution is here and if I'm right, I can still use colNames but need to get them together with colTypes, then inside resultSet.next() to call getType method for each as:
// this part of code is not tested
// this idea came to me writing this topic
while (resultSet.next()) {
val row = columns.toList.map(x => {
x.colType match {
case "string" => resultSet.getString(x.colName)
case "integer" => resultSet.getInt(x.colName)
case "decimal" => resultSet.getDecimal(x.colName)
case _ => resultSet.getString(x.colName)
})
item = row
}

Answer 1

You may try to use getColumnLabel instead of getColumnName
as documented
Gets the designated column's suggested title for use in printouts and displays. The suggested title is usually specified by the SQL AS clause. If a SQL AS is not specified, the value returned from getColumnLabel will be the same as the value returned by the getColumnName method.
Note that this is highly dependent on the used RDBM.
For Oracle both methods return the alias and there is no chance to get the original column name.