support drop index stmt

README.md

@@ -15,6 +15,7 @@ this is an oracle sql parser. ref: https://docs.oracle.com/en/database/oracle/or
 |Create table|Relational table|:heavy_check_mark:|:heavy_check_mark:|
 |Create index|Relational table|:heavy_check_mark:| |
 |Drop table|-|:heavy_check_mark:|:heavy_check_mark:|
+|Drop index|-|:heavy_check_mark:|:heavy_check_mark:|
 
 ## usage
 ```go

ast/base.go

@@ -9,6 +9,11 @@ type TableName struct {
 	Table  *element.Identifier
 }
 
+type IndexName struct {
+	Schema *element.Identifier
+	Index  *element.Identifier
+}
+
 type Collation struct {
 	Name *element.Identifier
 }

ast/ddl.go

@@ -123,4 +123,13 @@ type CreateIndexStmt struct {
 type DropTableStmt struct {
 	node
 	TableName *TableName
+}
+
+/*
+	Drop Index  Statement
+	see: https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/DROP-INDEX.html#GUID-F60F75DF-2866-4F93-BB7F-8FCE64BF67B6
+*/
+type DropIndexStmt struct {
+	node
+	IndexName *IndexName
 }