kaspersorensen commented on a change in pull request #208: the result of
column.getNativeType() may be null and add pagination function to the Hive sql.
URL: https://github.com/apache/metamodel/pull/208#discussion_r259643332
##########
File path:
jdbc/src/main/java/org/apache/metamodel/jdbc/dialects/HiveQueryRewriter.java
##########
@@ -18,18 +18,46 @@
*/
package org.apache.metamodel.jdbc.dialects;
+import java.util.List;
+import org.apache.metamodel.MetaModelException;
import org.apache.metamodel.jdbc.JdbcDataContext;
+import org.apache.metamodel.query.FromItem;
+import org.apache.metamodel.query.Query;
+import org.apache.metamodel.query.SelectItem;
import org.apache.metamodel.schema.ColumnType;
/**
* Query rewriter for Apache Hive
*/
-public class HiveQueryRewriter extends DefaultQueryRewriter {
+public class HiveQueryRewriter extends RowNumberQueryRewriter {
public HiveQueryRewriter(JdbcDataContext dataContext) {
super(dataContext);
}
+ @Override
+ public String rewriteQuery(Query query) {
+
+ Integer maxRows = query.getMaxRows();
+ Integer firstRow = query.getFirstRow();
+
+ if (maxRows == null && (firstRow == null || firstRow.intValue() == 1))
{
+ return super.rewriteQuery(query);
+ }
+
+ if ((firstRow == null || firstRow.intValue() == 1) && maxRows != null
&& maxRows > 0) {
+ // We prefer to use the "LIMIT n" approach, if
+ // firstRow is not specified.
+ return super.rewriteQuery(query) + " LIMIT " + maxRows;
+ } else {
+ return getRowNumberSql(query, maxRows, firstRow);
+ }
+
+ }
+
+
Review comment:
No need for the 4 line breaks
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