ddl parser api is missing in java sdk

[shawn-happy]

create ddl parser api for java sdk.

[lumianph]

thanks for the suggestion, @dl239 will follow up this issue BTW, can you please elaborate on your requirements and potential solutions about this issue? We are looking forward to your contribution.

[shawn-happy]

• requirements： I wish I had provided sql statements, tables and schemas of each table that could return the statement that created the table。
• solutions：
  1. create a virtual method called genDDL in sql_router.h, The method has two parameters: (string sql, map<string, vector<map<string, string>>> tableMap).

example: the sql parameter is a query statements such as : SELECT a.itemId as itemId, b.brandName as name, b.brandId as brandId, c.actionValue as label FROM a LAST JOIN c ON c.itemId = a.itemId LAST JOIN adinfo ON a.itemId = b.id;

the tableMap parameter is Is used to indicate the mapping between tables and schemas of each table: { "a": [ { "name": "itemId", "type": "string" }, { "name": "reqId", "type": "string" } ], "b": [ { "name": "id", "type": "string" } ], "c": [ { "name": "itemId", "type": "string" }, { "name": "reqId", "type": "string" } ] }

2. create rpc method in nameserver. proto and define ddl parser request and response e.g: rpc ExecuteDDLParser(DDLParserRequest) returns (DDLParserResponse); message DDLParserRequest{ optional string sql = 3; optional string table = 3; repeated openmldb.common.ColumnDesc column_desc= 1; }

message DDLParserResponse{ optional int32 code = 2; optional string msg = 3; repeated string ddl = 1; }

3. create virtual ExecuteDDLParser() in name_server_impl.h and Implement ExecuteDDLParser method in name_server_impl.cc void ExecuteDDLParser(RpcController* controller, const DDLParserRequest* request, DDLParserResponse* response, Closure* done);
4. create a method in ns_client.cc for sql_router can access rpc method

@dl239 @vagetablechicken please review this solution to give me some advice

[vagetablechicken]

Maybe ExtractIndexRequest is better, or DDLParseRequest, not parser request. We want to support tables, but request only has one table and its columns. You could try inner message, like:

message Request {
    message Table{
        optional table_name;
        repeated cols;
    }
   repeated Table tables;
}

[dl239]

Why add ExecuteDDLParser rpc interface to server? @shawn-happy

[shawn-happy]

i want to auto create table in server after genDDl statement @dl239