Re: [PR] [SPARK-48824][SQL] Add Identity Column SQL syntax [spark]

["cloud-fan (via GitHub)" <gi...@apache.org>]

cloud-fan commented on code in PR #47614:
URL: https://github.com/apache/spark/pull/47614#discussion_r1757262228


##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala:
##########
@@ -3616,11 +3623,63 @@ class AstBuilder extends DataTypeAstBuilder
   /**
    * Create a generation expression string.
    */
-  override def visitGenerationExpression(ctx: GenerationExpressionContext): String =
+  override def visitGeneratedColumn(ctx: GeneratedColumnContext): String =
     withOrigin(ctx) {
       getDefaultExpression(ctx.expression(), "GENERATED").originalSQL
     }
 
+  /**
+   * Parse and verify IDENTITY column definition.
+   *
+   * @param ctx      The parser context.
+   * @param dataType The data type of column defined as IDENTITY column. Used for verification.
+   * @return Tuple containing start, step and allowExplicitInsert.
+   */
+  protected def visitIdentityColumn(
+      ctx: IdentityColumnContext,
+      dataType: DataType): IdentityColumnSpec = {
+    if (dataType != LongType && dataType != IntegerType) {
+      throw QueryParsingErrors.identityColumnUnsupportedDataType(ctx, dataType.toString)
+    }
+    // We support two flavors of syntax:
+    // (1) GENERATED ALWAYS AS IDENTITY (...)
+    // (2) GENERATED BY DEFAULT AS IDENTITY (...)
+    // (1) forbids explicit inserts, while (2) allows.
+    val allowExplicitInsert = ctx.BY() != null && ctx.DEFAULT() != null
+    val (start, step) = visitIdentityColSpec(ctx.identityColSpec())
+
+    IdentityColumnSpec(start, step, allowExplicitInsert)
+  }
+
+  override def visitIdentityColSpec(ctx: IdentityColSpecContext): (Long, Long) = {
+    val defaultStart = 1
+    val defaultStep = 1
+    if (ctx == null) {
+      return (defaultStart, defaultStep)
+    }
+    var (start, step): (Option[Long], Option[Long]) = (None, None)
+    ctx.sequenceGeneratorOption().asScala.foreach { option =>
+      if (option.start != null) {
+        if (start.isDefined) {
+          throw QueryParsingErrors.identityColumnDuplicatedSequenceGeneratorOption(ctx, "START")
+        }
+        start = Some(option.start.getText.toLong)
+      } else if (option.step != null) {
+        if (step.isDefined) {
+          throw QueryParsingErrors.identityColumnDuplicatedSequenceGeneratorOption(ctx, "STEP")
+        }
+        step = Some(option.step.getText.toLong)
+        if (step.get == 0L) {
+          throw QueryParsingErrors.identityColumnIllegalStep(ctx)
+        }
+      } else {
+        throw throw SparkException

Review Comment:
   ```suggestion
           throw SparkException
   ```



-- 
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.

To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org