feat: adds view expressions (#165)

* feat: adds view expressions

* feat: adds meta tasks for view

* feat: adds view_info to CreateViewTask

* chore: rename create_or_replace to or_replace

proto/greptime/v1/ddl.proto

@@ -35,6 +35,8 @@ message DdlRequest {
     TruncateTableExpr truncate_table = 7;
     CreateFlowExpr create_flow = 8;
     DropFlowExpr drop_flow = 9;
+    CreateViewExpr create_view = 10;
+    DropViewExpr drop_view = 11;
   }
 }
 
@@ -60,6 +62,25 @@ message DropFlowExpr {
   bool drop_if_exists = 5;
 }
 
+// Create a view
+message CreateViewExpr {
+  string catalog_name = 1;
+  string schema_name = 2;
+  string view_name = 3;
+  bytes logical_plan = 4;
+  bool create_if_not_exists = 5;
+  bool or_replace = 6;
+}
+
+// Drop a view
+message DropViewExpr {
+  string catalog_name = 1;
+  string schema_name = 2;
+  string view_name = 3;
+  TableId view_id = 4;
+  bool drop_if_exists = 5;
+}
+
 message CreateTableExpr {
   string catalog_name = 1;
   string schema_name = 2;

proto/greptime/v1/meta/ddl.proto

@@ -68,6 +68,17 @@ message DropFlowTask {
     DropFlowExpr drop_flow = 1;
 }
 
+// Create a view task
+message CreateViewTask {
+    CreateViewExpr create_view = 1;
+    bytes view_info = 2;
+}
+
+// Drop a view task
+message DropViewTask {
+    DropViewExpr drop_view = 1;
+}
+
 message DdlTaskRequest {
     RequestHeader header = 1;
     QueryContext query_context = 64;
@@ -84,6 +95,8 @@ message DdlTaskRequest {
         CreateDatabaseTask create_database_task = 10;
         CreateFlowTask create_flow_task = 11;
         DropFlowTask drop_flow_task = 12;
+        CreateViewTask create_view_task = 13;
+        DropViewTask drop_view_task = 14;
      }
 }