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Hello,
I have been exploring functionality of the mORMot in regards to the MongoDB. And I have found that if I define a record like this:
TEmpl = class(TPersistent)
private
FCode: Integer;
FName: RawUTF8;
published
property Code: Integer read FCode write FCode;
property Name: RawUTF8 read FName write FName;
end;
TSQLMongoTest = class(TSQLRecord)
private
FEmpl1: TEmpl;
FEmpl2: Variant;
public
constructor Create; override;
destructor Destroy; override;
published
property Empl1: TEmpl read FEmpl1;
property Empl2: Variant read FEmpl2 write FEmpl2;
end;
and save it to a database:
TAutoFree.One(R, TSQLMongoTest.Create);
R.Empl1.Code := 23;
R.Empl1.Name := 'Empl1';
R.Empl2 := TDocVariant.NewObject(['Code', 23, 'Name', 'Empl2']);
Client.Add(R, True);
then the Empl2 is stored as a real "object" part of the MongoDB document but the Empl1 - as JSON in a string field:
{"_id":{"$numberInt":"1"},"Empl1":"{\"Code\":23,\"Name\":\"Empl1\"}","Empl2":{"Code":{"$numberInt":"23"},"Name":"Empl2"}}
After that, I can find the document using Eml2.Code but obviously not the Empl1.Code:
R := TSQLMongoTest.CreateAndFillPrepare(Client, 'Empl1.Code = ?', [23]);
try
while R.FillOne do
s := R.Empl1.Name; // Is not executed
finally
R.Free;
end;
R := TSQLMongoTest.CreateAndFillPrepare(Client, 'Empl2.Code = ?', [23]);
try
while R.FillOne do
s := R.Empl2.Name; // Executed
finally
R.Free;
end;
As far as I can understand, according to the documentation there should be no difference in my case between Empl2 and Empl1.
DocVariants are great! But I would like to use a predefined structure and compile-time checks as well. Is there a way to store a TObject/TPersistent/record property of a TSQLRecord descendant as an "object" part of a MongoDB document (not as JSON in a string field)?
Thank you in advance for any hints.
Best regards,
Sergey Gavrilov
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Searching 'Empl1.Code=?' should work in latest versions of mORMotMongoDB, IIRC.
Check https://synopse.info/files/html/Synopse … #TITLE_226 as reference.
Published records are not well supported by the compilers, so their support is preliminary.
But nested objects can be stored I guess. Check https://synopse.info/files/html/Synopse … ml#TITL_52
What we usually do is use T*ObjArray published fields: register a dynamic array of one TObject class to the serializer, then the array would be stored as a BSON list.
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