[GitHub] [flink] godfreyhe commented on a change in pull request #11892: [FLINK-17112][table] Support DESCRIBE statement in Flink SQL
godfreyhe commented on a change in pull request #11892:
URL: https://github.com/apache/flink/pull/11892#discussion_r422050608
##
File path:
flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/api/internal/TableEnvImpl.scala
##
@@ -766,7 +768,29 @@ abstract class TableEnvImpl(
case descOperation: DescribeTableOperation =>
val result = catalogManager.getTable(descOperation.getSqlIdentifier)
if (result.isPresent) {
- buildShowResult(Array(result.get().getTable.getSchema.toString))
+ val schema = result.get.getTable.getSchema
+ val fieldToWatermark =
+schema
+ .getWatermarkSpecs
+ .map(w => (w.getRowtimeAttribute, w.getWatermarkExpr)).toMap
+ val fieldToPrimaryKey = new JHashMap[String, String]()
+ if (schema.getPrimaryKey.isPresent) {
+val columns = schema.getPrimaryKey.get.getColumns.asScala
+columns.foreach(c => fieldToPrimaryKey.put(c,
s"PRI(${columns.mkString(",")})"))
+ }
+ val data = Array.ofDim[String](schema.getFieldCount, 6)
+ schema.getTableColumns.asScala.zipWithIndex.foreach {
+case (c, i) => {
+ val logicalType = c.getType.getLogicalType
+ data(i)(0) = c.getName
+ data(i)(1) = StringUtils.removeEnd(logicalType.toString, " NOT
NULL")
+ data(i)(2) = if (logicalType.isNullable) "true" else "false"
+ data(i)(3) = fieldToPrimaryKey.getOrDefault(c.getName, "(NULL)")
+ data(i)(4) = c.getExpr.orElse("(NULL)")
+ data(i)(5) = fieldToWatermark.getOrDefault(c.getName, "(NULL)")
+}
+ }
+ buildShowResult(Array("name", "type", "null", "key", "compute
column", "watermark"), data)
Review comment:
ditto
##
File path:
flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/api/internal/TableEnvironmentImpl.java
##
@@ -861,23 +865,32 @@ private TableResult executeOperation(Operation operation)
{
catalogManager.getTable(describeTableOperation.getSqlIdentifier());
if (result.isPresent()) {
TableSchema schema =
result.get().getTable().getSchema();
- String[][] rows = Stream.concat(
+ Map fieldToWatermark =
+ schema.getWatermarkSpecs()
+ .stream()
+
.collect(Collectors.toMap(WatermarkSpec::getRowtimeAttribute,
WatermarkSpec::getWatermarkExpr));
+
+ Map fieldToPrimaryKey = new
HashMap<>();
+ schema.getPrimaryKey().ifPresent((p) -> {
+ List columns = p.getColumns();
+ columns.forEach((c) ->
fieldToPrimaryKey.put(c, String.format("PRI(%s)", String.join(",", columns;
+ });
+
+ String[][] rows =
schema.getTableColumns()
.stream()
- .map((c) -> new
String[]{
+ .map((c) -> {
+ LogicalType
logicalType = c.getType().getLogicalType();
+ return new
String[]{
c.getName(),
-
c.getType().getLogicalType().toString(),
-
c.getExpr().orElse("(NULL)")}),
- schema.getWatermarkSpecs()
- .stream()
- .map((w) -> new
String[]{
- "WATERMARK",
- "(NULL)",
-
w.getWatermarkExpr()
- })
- ).toArray(String[][]::new);
-
- return buildShowResult(new String[]{"name",
"type", "expr"}, rows);
+
StringUtils.removeEnd(logicalType.toString(), " NOT NULL"),
+
logicalType.isNullable() ? "true" : "false",
+
fieldToPrimaryKey.getOrDefault(c.getName(), "(NULL)"),
+
[GitHub] [flink] godfreyhe commented on a change in pull request #11892: [FLINK-17112][table] Support DESCRIBE statement in Flink SQL
godfreyhe commented on a change in pull request #11892:
URL: https://github.com/apache/flink/pull/11892#discussion_r415486982
##
File path:
flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/api/internal/TableEnvImpl.scala
##
@@ -721,6 +721,15 @@ abstract class TableEnvImpl(
dropViewOperation.isIfExists)
}
TableResultImpl.TABLE_RESULT_OK
+ case descOperation: DescribeTableOperation =>
+val result = catalogManager.getTable(descOperation.getSqlIdentifier)
+if (result.isPresent) {
+ buildShowResult(Array(result.get().getTable.getSchema.toString))
Review comment:
I find SQL parser support column comments
([see](https://github.com/apache/flink/blob/master/flink-table/flink-sql-parser/src/test/java/org/apache/flink/sql/parser/FlinkSqlParserImplTest.java#L225)),
but we do not store the comments into TableSchema. we ignore `comment` column.
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[GitHub] [flink] godfreyhe commented on a change in pull request #11892: [FLINK-17112][table] Support DESCRIBE statement in Flink SQL
godfreyhe commented on a change in pull request #11892:
URL: https://github.com/apache/flink/pull/11892#discussion_r415473253
##
File path:
flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/api/internal/TableEnvImpl.scala
##
@@ -721,6 +721,15 @@ abstract class TableEnvImpl(
dropViewOperation.isIfExists)
}
TableResultImpl.TABLE_RESULT_OK
+ case descOperation: DescribeTableOperation =>
+val result = catalogManager.getTable(descOperation.getSqlIdentifier)
+if (result.isPresent) {
+ buildShowResult(Array(result.get().getTable.getSchema.toString))
Review comment:
I find the print (through `TableResult#print`) result of `describe xx`
looks a little strange:
```
++
| result |
++
| root
|-- a: INT
|-- b: S... |
++
1 row in set
```
Users have to parse the unstructured result if he/she want to use the result
to do sth through TableResult#collect method.
How about we return a structured tableau result, e.g.
```
+-+-+-+
| name| type | comment |
+-+-+-+
| a | INT | |
| b | STRING | |
+-+-+-+
2 rows in set
```
This is different from the describe result in SQL client.
Anther thing we should consider is how to print `watermarkSpecs` and compute
column.
How about we add a column named `expr` to represent `watermarkSpecs` and
compute column.
```
+-+-+-+-+
| name| type| comment | expr |
+-+-+-+-+
| a |INT | | (NULL) |
| b |INT | | a + 1 |
| c |TIMESTAMP(3) | | (NULL) |
| WATERMARK | (NULL) | | c AS now() |
+-+-+-+-+
```
##
File path:
flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/api/internal/TableEnvImpl.scala
##
@@ -721,6 +721,15 @@ abstract class TableEnvImpl(
dropViewOperation.isIfExists)
}
TableResultImpl.TABLE_RESULT_OK
+ case descOperation: DescribeTableOperation =>
+val result = catalogManager.getTable(descOperation.getSqlIdentifier)
+if (result.isPresent) {
+ buildShowResult(Array(result.get().getTable.getSchema.toString))
Review comment:
cc @twalthr
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