[mongoDB] How to use for dvArray kind of TDocVariant

bigheart · 2014-10-02 06:36:33

Hi!

I got some problem when using mORMot for TMongoCollection.AggregateDoc

var
LDoc: variant;

LDoc:= Coll.AggregateDoc('{$sort:{_id:-1}},{$limit:1}', []); ===> single value is returned, OK!

but

LDoc:= Coll.AggregateDoc('{$sort:{_id:-1}},{$limit:5}', []); ===> multiple values are returned(5 values)

In this case, how to access the second value like: Lvar[1].value;

According to the manual:

if LDoc._kind = ord(dvArray) then ===> error occured here that "Invalid variant type 0 invoke"
begin
showmessage(LDoc._(1));
end;

Help me please!

ab · 2014-10-02 08:41:51

I suspect your returned LDoc is NOT a TDocVariant, but null.

Could you debug and step in TMongoConnection.RunCommand() to see what is returned by the server?

bigheart · 2014-10-02 09:13:58

I have executed as below:

var
AQry: string;
LDoc: variant;

AQry := '{ aggregate: "COLLECTNAME", pipeline: [{$sort:{_id:-1}},{$limit:5}], allowDiskUse: true}';
FDB.RunCommand(BSONVariant(AQry), LDoc);

with debugging LDoc, LDoc has a data, not null;

but

showmessage(Utf8ToString(VariantToUtf8(LDoc.Value))); ===> "null" displayed

Last edited by bigheart (2014-10-02 09:15:10)

ab · 2014-10-03 07:37:29

What is LDoc content?

bigheart · 2014-10-10 08:55:25

LDoc contents are datetime and "a":"1" format data.

When debugging with "class procedure TDocVariant.GetSingleOrDefault" function in SynCommons.pas is excuted,

recursive call itself one time.

Trace into that function again,

TDocVariant(DocVariantArray).count is 5,

also TDocVariantData(DocVariantArray).Values[0] ~ TDocVariantData(DocVariantArray).Values[4] has exact data what i want.

But condition as "TDocVariant(DocVariantArray).count <> 1" in GetSingleOrDefault(...) function,

result := default;

is excuted;

And next "result" is not assigned.

How can i have multiple data from AggregateDoc(...).

sodri126 · 2019-10-03 10:15:33

Yes, I got error when the data is more than 2. How to solve it when I got more than one in AggregateDoc()?

ab · 2019-10-03 19:48:27

TDocVariant(DocVariantArray) is not correct.
You need to transtype as TDocVariantVariant(DocVariantArray).

sodri126 · 2019-10-06 16:52:03

is any TDocVariantVariant in mormot? because i have already typed it and Undefined the class

pvn0 · 2019-10-07 07:41:18

sodri126 wrote:

is any TDocVariantVariant in mormot? because i have already typed it and Undefined the class

It was a typo error, he meant TDocVariantData

mORMot Open Source

#1 2014-10-02 06:36:33

[mongoDB] How to use for dvArray kind of TDocVariant

#2 2014-10-02 08:41:51

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#3 2014-10-02 09:13:58

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#4 2014-10-03 07:37:29

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#5 2014-10-10 08:55:25

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#6 2019-10-03 10:15:33

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#7 2019-10-03 19:48:27

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#8 2019-10-06 16:52:03

Re: [mongoDB] How to use for dvArray kind of TDocVariant

#9 2019-10-07 07:41:18

Re: [mongoDB] How to use for dvArray kind of TDocVariant

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