wuchong commented on a change in pull request #12571: URL: https://github.com/apache/flink/pull/12571#discussion_r438531251
########## File path: docs/dev/table/connectors/formats/csv.zh.md ########## @@ -0,0 +1,330 @@ +--- +title: "CSV Format" +nav-title: CSV +nav-parent_id: sql-formats +nav-pos: 1 +--- +<!-- +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. +--> + +<span class="label label-info">Format: Serialization Schema</span> +<span class="label label-info">Format: Deserialization Schema</span> + +* This will be replaced by the TOC +{:toc} + +The [CSV](https://en.wikipedia.org/wiki/Comma-separated_values) format allows to read and write CSV data based on an CSV schema. Currently, the CSV schema is derived from table schema. + +Dependencies +------------ + +In order to setup the CSV format, the following table provides dependency information for both projects using a build automation tool (such as Maven or SBT) and SQL Client with SQL JAR bundles. + +| Maven dependency | SQL Client JAR | +| :----------------- | :----------------------| +| `flink-csv` | The `flink-csv-{{site.version}}.jar` is a built-in jar of SQL-CLI. | + +How to create a table with CSV format +---------------- + +Here is an example to create a table using Kafka connector and CSV format. + +<div class="codetabs" markdown="1"> +<div data-lang="SQL" markdown="1"> +{% highlight sql %} +CREATE TABLE user_behavior ( + user_id BIGINT, + item_id BIGINT, + category_id BIGINT, + behavior STRING, + ts TIMESTAMP(3) +) WITH ( + 'connector' = 'kafka', + 'topic' = 'user_behavior', + 'properties.bootstrap.servers' = 'localhost:9092', + 'properties.group.id' = 'testGroup', + 'format' = 'csv' +) +{% endhighlight %} +</div> +</div> + +Format Options +---------------- + +<table class="table table-bordered"> + <thead> + <tr> + <th class="text-left" style="width: 25%">Option</th> + <th class="text-center" style="width: 8%">Required</th> + <th class="text-center" style="width: 7%">Default</th> + <th class="text-center" style="width: 10%">Type</th> + <th class="text-center" style="width: 50%">Description</th> + </tr> + </thead> + <tbody> + <tr> + <td><h5>format</h5></td> + <td>required</td> + <td style="word-wrap: break-word;">(none)</td> + <td>String</td> + <td>Specify what format to use, here should be 'csv'.</td> + </tr> + <tr> + <td><h5>field-delimiter</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;"><code>,</code></td> + <td>String</td> + <td>Field delimiter character (',' by default).</td> + </tr> + <tr> + <td><h5>line-delimiter</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;"><code>\n</code></td> + <td>String</td> + <td>Line delimiter ('\n' by default, otherwise + '\r' or '\r\n' are allowed), unicode is supported if + the delimiter is an invisible special character, + e.g. U&'\\000D' is the unicode representation of carriage return '\r' + e.g. U&'\\000A' is the unicode representation of line feed '\n'.</td> + </tr> + <tr> + <td><h5>disable-quote-character</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;">false</td> + <td>Boolean</td> + <td>Flag to disabled quote character for enclosing field values (false by default) + if true, quote-character can not be set.</td> + </tr> + <tr> + <td><h5>quote-character</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;"><code>"</code></td> + <td>String</td> + <td>Quote character for enclosing field values ('"' by default).</td> + </tr> + <tr> + <td><h5>allow-comments</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;">false</td> + <td>Boolean</td> + <td>Flag to ignore comment lines that start with '#' + (disabled by default); + if enabled, make sure to also ignore parse errors to allow empty rows.</td> + </tr> + <tr> + <td><h5>ignore-parse-errors</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;">false</td> + <td>Boolean</td> + <td>Flag to skip fields and rows with parse errors instead of failing; + fields are set to null in case of errors.</td> + </tr> + <tr> + <td><h5>array-element-delimiter</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;"><code>;</code></td> + <td>String</td> + <td>Array element delimiter string for separating + array and row element values (';' by default).</td> + </tr> + <tr> + <td><h5>escape-character</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;">(none)</td> + <td>String</td> + <td>Escape character for escaping values (disabled by default).</td> + </tr> + <tr> + <td><h5>null-literal</h5></td> + <td>optional</td> + <td style="word-wrap: break-word;">(none)</td> + <td>String</td> + <td>Null literal string that is interpreted as a + null value (disabled by default).</td> + </tr> + </tbody> +</table> + +Data Type Mapping +---------------- + +Currently, the CSV schema is always derived from table schema. Explicitly defining an CSV schema is not supported yet. + +Flink CSV format uses utility class `com.fasterxml.jackson.databind.node.ObjectNode` (for serialization) and `com.fasterxml.jackson.databind.JsonNode` (for deserialization) provided by `jackson` to convert Flink Data Types to and from CSV text. + +The following table lists the type mapping from Flink type to CSV type. Review comment: I think we can copy the data type mapping of JSON to here. They are almost the same (except CSV doesn't some types, e.g. MAP). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
