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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (METAMODEL-244) Ability to specify column names for datastores that may not have named columns
Date Sat, 23 Apr 2016 20:25:12 GMT

    [ https://issues.apache.org/jira/browse/METAMODEL-244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15255377#comment-15255377
] 

ASF GitHub Bot commented on METAMODEL-244:
------------------------------------------

Github user kaspersorensen commented on a diff in the pull request:

    https://github.com/apache/metamodel/pull/96#discussion_r60834460
  
    --- Diff: core/src/main/java/org/apache/metamodel/schema/builder/ColumnNamingStrategy.java
---
    @@ -0,0 +1,37 @@
    +/**
    + * 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.builder;
    +
    +/**
    + * A strategy that defines how columns are logically named. Such strategies are
    + * mostly used when a particular datastore is not itself intrinsically
    + * specifying the column name.
    + */
    +public interface ColumnNamingStrategy {
    +
    +    /**
    +     * Provides the name to apply for a given column.
    +     * 
    +     * @param ctx
    +     *            the context of the column naming taking place. This contains
    +     *            column index, intrinsic name etc. if available.
    +     * @return the name to provide to the column.
    +     */
    +    public String getNextColumnName(ColumnNamingContext ctx);
    --- End diff --
    
    I'm wondering if this method should reside here or in some object that is scoped just
for the individual table. Because right now the interface seems to be global fir many tables
but implementations typically need state which is scoped only for the duration of naming a
single table.


> 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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