Github user nareshpr commented on a diff in the pull request:
https://github.com/apache/incubator-carbondata/pull/641#discussion_r106112796
--- Diff:
integration/spark-common/src/main/scala/org/apache/carbondata/spark/util/CarbonScalaUtil.scala
---
@@ -194,4 +196,102 @@ object CarbonScalaUtil {
}
}
}
+
+ /**
+ * This method will validate a column for its data type and check
whether the column data type
+ * can be modified and update if conditions are met
+ *
+ * @param dataTypeInfo
+ * @param carbonColumn
+ */
+ def validateColumnDataType(dataTypeInfo: DataTypeInfo, carbonColumn:
CarbonColumn): Unit = {
+ carbonColumn.getDataType.getName match {
+ case "INT" =>
+ if (!dataTypeInfo.dataType.equals("bigint")) {
+ sys
+ .error(s"Given column ${ carbonColumn.getColName } with data
type ${
+ carbonColumn
+ .getDataType.getName
+ } cannot be modified. Int can only be changed to bigInt")
+ }
+ case "DECIMAL" =>
+ if (!dataTypeInfo.dataType.equals("decimal")) {
+ sys
+ .error(s"Given column ${ carbonColumn.getColName } with data
type ${
+ carbonColumn.getDataType.getName
+ } cannot be modified. Decimal can be only be changed to
Decimal of higher precision")
+ }
+ if (dataTypeInfo.precision <=
carbonColumn.getColumnSchema.getPrecision) {
+ sys
+ .error(s"Given column ${
+ carbonColumn
+ .getColName
+ } cannot be modified. Specified precision value ${
+ dataTypeInfo
+ .precision
+ } should be greater or equal to current precision value ${
+ carbonColumn.getColumnSchema
+ .getPrecision
+ }")
+ } else if (dataTypeInfo.scale <=
carbonColumn.getColumnSchema.getScale) {
+ sys
+ .error(s"Given column ${
+ carbonColumn
+ .getColName
+ } cannot be modified. Specified scale value ${
+ dataTypeInfo
+ .scale
+ } should be greater or equal to current scale value ${
+ carbonColumn.getColumnSchema
+ .getScale
+ }")
+ } else {
+ // difference of precision and scale specified by user should
not be less than the
+ // difference of already existing precision and scale else it
will result in data loss
+ val carbonColumnPrecisionScaleDiff =
carbonColumn.getColumnSchema.getPrecision -
+
carbonColumn.getColumnSchema.getScale
+ val dataInfoPrecisionScaleDiff = dataTypeInfo.precision -
dataTypeInfo.scale
+ if (dataInfoPrecisionScaleDiff < carbonColumnPrecisionScaleDiff)
{
+ sys
+ .error(s"Given column ${
+ carbonColumn
+ .getColName
+ } cannot be modified. Specified precision and scale values
will lead to data loss")
+ }
+ }
+ case _ =>
+ sys
+ .error(s"Given column ${ carbonColumn.getColName } with data
type ${
+ carbonColumn
+ .getDataType.getName
+ } cannot be modified. Only Int and Decimal data types are
allowed for modification")
+ }
+ }
+
+ /**
+ * This method will create a copy of the same object
+ *
+ * @param thriftColumnSchema object to be cloned
+ * @return
+ */
+ def createColumnSchemaCopyObject(thriftColumnSchema:
org.apache.carbondata.format.ColumnSchema)
--- End diff --
Done
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