wuchong commented on a change in pull request #11493:
[FLINK-16160][table-common] Support computed column, proctime and watermark in
Schema descriptor
URL: https://github.com/apache/flink/pull/11493#discussion_r399106947
##########
File path:
flink-table/flink-table-common/src/main/java/org/apache/flink/table/descriptors/Schema.java
##########
@@ -85,11 +111,25 @@ public Schema schema(TableSchema schema) {
* @param fieldType the type information of the field
*/
public Schema field(String fieldName, DataType fieldType) {
- addField(fieldName,
fieldType.getLogicalType().asSerializableString());
- return this;
+ return field(fieldName, fieldType, null);
}
+ /**
+ * Adds a field with the field name and the data type. Required.
+ * This method can be called multiple times. The call order of this
method defines
+ * also the order of the fields in a row.
+ *
+ * @param fieldName the field name
+ * @param fieldType the type information of the field
+ * @param fieldExpr Computed column expression, it should be a
SQL-style expression whose
+ * identifiers should be all quoted and expanded.
+ */
+ public Schema field(String fieldName, DataType fieldType, String
fieldExpr) {
Review comment:
The `Schema` descriptor API should follow the DDL pattern, i.e. we shouldn't
force users to give a quoted expression and an expression result type.
It is hard to determin what the result type is of `myfunc(myfunc1(a), b,
c)`.
It is hard to write a quoted expression, e.g.
```
`myfunc`(`myfunc1`(`a`), `b`, `c`)
```
Could the planner to quote the expression and derive data type?
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