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https://issues.apache.org/jira/browse/METAMODEL-244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15257983#comment-15257983
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ASF GitHub Bot commented on METAMODEL-244:
------------------------------------------
Github user LosD commented on a diff in the pull request:
https://github.com/apache/metamodel/pull/96#discussion_r61075904
--- Diff:
core/src/main/java/org/apache/metamodel/schema/naming/UniqueColumnNamingStrategy.java
---
@@ -0,0 +1,62 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.metamodel.schema.naming;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A {@link ColumnNamingStrategy} that uses the intrinsic column names, but
+ * ensures that all column names are unique. When duplicate names are
+ * encountered a number will be appended yielding column names like "name",
+ * "name1", "name2" etc.
+ */
+public class UniqueColumnNamingStrategy implements ColumnNamingStrategy {
+
+ private static final long serialVersionUID = 1L;
+
+ @Override
+ public ColumnNamingSession startColumnNamingSession() {
+ return new ColumnNamingSession() {
+
+ private final Set<String> names = new HashSet<>();
+
+ @Override
+ public String getNextColumnName(ColumnNamingContext ctx) {
+ final String intrinsicName = ctx.getIntrinsicColumnName();
+ boolean unique = names.add(intrinsicName);
+ if (unique) {
+ return intrinsicName;
+ }
+
+ String newName = null;
+ for (int i = 2; !unique; i++) {
+ newName = intrinsicName + i;
--- End diff --
Wouldn't an underscore before be better? Some columns may already end with
numbers.
That could lead to endless confusion, e.g. something like "is_iso9001"
would become "is_iso90011", which is a different standard (no, I have no good
reason why this exact example would ever happen, but it's easily a general
problem :))
> Ability to specify column names for datastores that may not have named columns
> ------------------------------------------------------------------------------
>
> Key: METAMODEL-244
> URL: https://issues.apache.org/jira/browse/METAMODEL-244
> Project: Apache MetaModel
> Issue Type: New Feature
> Reporter: Kasper Sørensen
> Assignee: Kasper Sørensen
>
> Some datastores don't necesarily define the column names/headers, just the
> data. Therefore it is sometimes needed to define column names manually - or
> even via some pluggable interface that would allow a custom naming strategy.
> I can think of the following modules where this would be relevant:
> * csv
> * fixed-width
> * excel
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