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@@ -31,6 +31,7 @@ type
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FQuery:string; // last prepared query, with :ParamName converted to ?
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FParamIndex:TParamBinding; // maps the i-th parameter in the query to the TParams passed to PrepareStatement
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FParamBuf:array of pointer; // buffers that can be used to bind the i-th parameter in the query
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+ FBlobStreams:TList; // list of Blob TMemoryStreams stored in field buffers (we need this currently as we can't hook into the freeing of TBufDataset buffers)
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public
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constructor Create(Connection:TODBCConnection);
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destructor Destroy; override;
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@@ -101,8 +102,8 @@ type
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public
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property Environment:TODBCEnvironment read FEnvironment;
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published
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- property Driver:string read FDriver write FDriver; // will be passed as DRIVER connection parameter
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- property FileDSN:string read FFileDSN write FFileDSN; // will be passed as FILEDSN parameter
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+ property Driver:string read FDriver write FDriver; // will be passed as DRIVER connection parameter
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+ property FileDSN:string read FFileDSN write FFileDSN; // will be passed as FILEDSN parameter
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// Redeclare properties from TSQLConnection
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property Password; // will be passed as PWD connection parameter
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property Transaction;
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@@ -126,7 +127,7 @@ type
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implementation
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uses
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- Math; // for the Min proc
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+ Math, DBConst;
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const
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DefaultEnvironment:TODBCEnvironment = nil;
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@@ -351,7 +352,8 @@ var
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OutConnectionString:string;
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ActualLength:SQLSMALLINT;
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begin
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- inherited DoInternalConnect;
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+ // Do not call the inherited method as it checks for a non-empty DatabaseName, and we don't even use DatabaseName!
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+ // inherited DoInternalConnect;
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// make sure we have an environment
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if not Assigned(FEnvironment) then
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@@ -382,7 +384,7 @@ begin
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SQL_HANDLE_DBC,FDBCHandle,Format('Could not connect with connection string "%s".',[ConnectionString])
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);
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-// commented out as the OutConenctionString is not used further at the moment
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+// commented out as the OutConnectionString is not used further at the moment
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// if ActualLength<BufferLength-1 then
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// SetLength(OutConnectionString,ActualLength); // fix completed connection string length
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@@ -520,6 +522,8 @@ begin
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end;
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function TODBCConnection.LoadField(cursor: TSQLCursor; FieldDef: TFieldDef; buffer: pointer): boolean;
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+const
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+ DEFAULT_BLOB_BUFFER_SIZE = 1024;
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var
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ODBCCursor:TODBCCursor;
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StrLenOrInd:SQLINTEGER;
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@@ -527,6 +531,9 @@ var
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ODBCTimeStruct:SQL_TIME_STRUCT;
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ODBCTimeStampStruct:SQL_TIMESTAMP_STRUCT;
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DateTime:TDateTime;
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+ BlobBuffer:pointer;
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+ BlobBufferSize,BytesRead:SQLINTEGER;
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+ BlobMemoryStream:TMemoryStream;
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Res:SQLRETURN;
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begin
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ODBCCursor:=cursor as TODBCCursor;
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@@ -578,27 +585,91 @@ begin
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Res:=SQLGetData(ODBCCursor.FSTMTHandle, FieldDef.Index+1, SQL_C_BINARY, buffer, FieldDef.Size, @StrLenOrInd);
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ftVarBytes: // mapped to TVarBytesField
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Res:=SQLGetData(ODBCCursor.FSTMTHandle, FieldDef.Index+1, SQL_C_BINARY, buffer, FieldDef.Size, @StrLenOrInd);
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+ ftBlob, ftMemo: // BLOBs
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+ begin
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+ // Try to discover BLOB data length
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+ Res:=SQLGetData(ODBCCursor.FSTMTHandle, FieldDef.Index+1, SQL_C_BINARY, buffer, 0, @StrLenOrInd);
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+ ODBCCheckResult(Res, SQL_HANDLE_STMT, ODBCCursor.FSTMTHandle, Format('Could not get field data for field ''%s'' (index %d).',[FieldDef.Name, FieldDef.Index+1]));
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+ // Read the data if not NULL
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+ if StrLenOrInd<>SQL_NULL_DATA then
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+ begin
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+ // Determine size of buffer to use
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+ if StrLenOrInd<>SQL_NO_TOTAL then
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+ BlobBufferSize:=StrLenOrInd
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+ else
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+ BlobBufferSize:=DEFAULT_BLOB_BUFFER_SIZE;
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+ try
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+ // init BlobBuffer and BlobMemoryStream to nil pointers
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+ BlobBuffer:=nil;
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+ BlobMemoryStream:=nil;
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+ if BlobBufferSize>0 then // Note: zero-length BLOB is represented as nil pointer in the field buffer to save memory usage
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+ begin
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+ // Allocate the buffer and memorystream
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+ BlobBuffer:=GetMem(BlobBufferSize);
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+ BlobMemoryStream:=TMemoryStream.Create;
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+ // Retrieve data in parts (or effectively in one part if StrLenOrInd<>SQL_NO_TOTAL above)
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+ repeat
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+ Res:=SQLGetData(ODBCCursor.FSTMTHandle, FieldDef.Index+1, SQL_C_BINARY, BlobBuffer, BlobBufferSize, @StrLenOrInd);
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+ ODBCCheckResult(Res, SQL_HANDLE_STMT, ODBCCursor.FSTMTHandle, Format('Could not get field data for field ''%s'' (index %d).',[FieldDef.Name, FieldDef.Index+1]));
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+ // Append data in buffer to memorystream
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+ if (StrLenOrInd=SQL_NO_TOTAL) or (StrLenOrInd>BlobBufferSize) then
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+ BytesRead:=BlobBufferSize
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+ else
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+ BytesRead:=StrLenOrInd;
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+ BlobMemoryStream.Write(BlobBuffer^, BytesRead);
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+ until Res=SQL_SUCCESS;
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+ end;
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+ // Store memorystream pointer in Field buffer and in the cursor's FBlobStreams list
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+ TObject(buffer^):=BlobMemoryStream;
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+ if BlobMemoryStream<>nil then
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+ ODBCCursor.FBlobStreams.Add(BlobMemoryStream);
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+ // Set BlobMemoryStream to nil, so it won't get freed in the finally block below
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+ BlobMemoryStream:=nil;
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+ finally
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+ BlobMemoryStream.Free;
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+ if BlobBuffer<>nil then
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+ Freemem(BlobBuffer,BlobBufferSize);
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+ end;
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+ end;
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+ end;
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// TODO: Loading of other field types
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else
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raise EODBCException.CreateFmt('Tried to load field of unsupported field type %s',[Fieldtypenames[FieldDef.DataType]]);
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end;
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- ODBCCheckResult(Res,SQL_HANDLE_STMT, ODBCCursor.FSTMTHandle, Format('Could not get field data for field ''%s'' (index %d).',[FieldDef.Name, FieldDef.Index+1]));
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+ ODBCCheckResult(Res, SQL_HANDLE_STMT, ODBCCursor.FSTMTHandle, Format('Could not get field data for field ''%s'' (index %d).',[FieldDef.Name, FieldDef.Index+1]));
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Result:=StrLenOrInd<>SQL_NULL_DATA; // Result indicates whether the value is non-null
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// writeln(Format('Field.Size: %d; StrLenOrInd: %d',[FieldDef.Size, StrLenOrInd]));
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end;
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function TODBCConnection.CreateBlobStream(Field: TField; Mode: TBlobStreamMode): TStream;
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+var
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+ ODBCCursor: TODBCCursor;
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+ BlobMemoryStream, BlobMemoryStreamCopy: TMemoryStream;
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begin
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- // TODO: implement TODBCConnection.CreateBlobStream
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- Result:=nil;
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+ if (Mode=bmRead) and not Field.IsNull then
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+ begin
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+ Field.GetData(@BlobMemoryStream);
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+ BlobMemoryStreamCopy:=TMemoryStream.Create;
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+ if BlobMemoryStream<>nil then
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+ BlobMemoryStreamCopy.LoadFromStream(BlobMemoryStream);
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+ Result:=BlobMemoryStreamCopy;
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+ end
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+ else
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+ Result:=nil;
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end;
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procedure TODBCConnection.FreeFldBuffers(cursor: TSQLCursor);
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var
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ODBCCursor:TODBCCursor;
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+ i: integer;
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begin
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ODBCCursor:=cursor as TODBCCursor;
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+
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+ // Free TMemoryStreams in cursor.FBlobStreams and clear it
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+ for i:=0 to ODBCCursor.FBlobStreams.Count-1 do
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+ TObject(ODBCCursor.FBlobStreams[i]).Free;
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+ ODBCCursor.FBlobStreams.Clear;
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ODBCCheckResult(
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SQLFreeStmt(ODBCCursor.FSTMTHandle, SQL_CLOSE),
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@@ -608,14 +679,15 @@ end;
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procedure TODBCConnection.AddFieldDefs(cursor: TSQLCursor; FieldDefs: TFieldDefs);
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const
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- ColNameDefaultLength = 40; // should be > 0, because an ansistring of length 0 is a nil pointer instead of a pointer to a #0
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+ ColNameDefaultLength = 40; // should be > 0, because an ansistring of length 0 is a nil pointer instead of a pointer to a #0
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+ TypeNameDefaultLength = 80; // idem
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var
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ODBCCursor:TODBCCursor;
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ColumnCount:SQLSMALLINT;
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i:integer;
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- ColNameLength,DataType,DecimalDigits,Nullable:SQLSMALLINT;
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+ ColNameLength,TypeNameLength,DataType,DecimalDigits,Nullable:SQLSMALLINT;
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ColumnSize:SQLUINTEGER;
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- ColName:string;
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+ ColName,TypeName:string;
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FieldType:TFieldType;
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FieldSize:word;
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begin
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@@ -668,10 +740,10 @@ begin
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case DataType of
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SQL_CHAR: begin FieldType:=ftFixedChar; FieldSize:=ColumnSize+1; end;
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SQL_VARCHAR: begin FieldType:=ftString; FieldSize:=ColumnSize+1; end;
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- SQL_LONGVARCHAR: begin FieldType:=ftString; FieldSize:=ColumnSize+1; end; // no fixed maximum length; make ftMemo when blobs are supported
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+ SQL_LONGVARCHAR: begin FieldType:=ftMemo; FieldSize:=sizeof(pointer); end; // is a blob
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SQL_WCHAR: begin FieldType:=ftWideString; FieldSize:=ColumnSize+1; end;
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SQL_WVARCHAR: begin FieldType:=ftWideString; FieldSize:=ColumnSize+1; end;
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- SQL_WLONGVARCHAR: begin FieldType:=ftWideString; FieldSize:=ColumnSize+1; end; // no fixed maximum length; make ftMemo when blobs are supported
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+ SQL_WLONGVARCHAR: begin FieldType:=ftMemo; FieldSize:=sizeof(pointer); end; // is a blob
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SQL_DECIMAL: begin FieldType:=ftFloat; FieldSize:=0; end;
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SQL_NUMERIC: begin FieldType:=ftFloat; FieldSize:=0; end;
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SQL_SMALLINT: begin FieldType:=ftSmallint; FieldSize:=0; end;
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@@ -684,12 +756,12 @@ begin
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SQL_BIGINT: begin FieldType:=ftLargeint; FieldSize:=0; end;
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SQL_BINARY: begin FieldType:=ftBytes; FieldSize:=ColumnSize; end;
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SQL_VARBINARY: begin FieldType:=ftVarBytes; FieldSize:=ColumnSize; end;
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- SQL_LONGVARBINARY: begin FieldType:=ftBlob; FieldSize:=ColumnSize; end;
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+ SQL_LONGVARBINARY: begin FieldType:=ftBlob; FieldSize:=sizeof(pointer); end; // is a blob
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SQL_TYPE_DATE: begin FieldType:=ftDate; FieldSize:=0; end;
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SQL_TYPE_TIME: begin FieldType:=ftTime; FieldSize:=0; end;
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SQL_TYPE_TIMESTAMP:begin FieldType:=ftDateTime; FieldSize:=0; end;
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{ SQL_TYPE_UTCDATETIME:FieldType:=ftUnknown;}
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-{ SQL_TYPE_UTCTIME: FieldType:=ftUnknown; }
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+{ SQL_TYPE_UTCTIME: FieldType:=ftUnknown;}
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{ SQL_INTERVAL_MONTH: FieldType:=ftUnknown;}
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{ SQL_INTERVAL_YEAR: FieldType:=ftUnknown;}
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{ SQL_INTERVAL_YEAR_TO_MONTH: FieldType:=ftUnknown;}
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@@ -707,12 +779,48 @@ begin
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else
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begin FieldType:=ftUnknown; FieldSize:=ColumnSize; end
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end;
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-
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+
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if (FieldType in [ftString,ftFixedChar]) and // field types mapped to TStringField
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(FieldSize >= dsMaxStringSize) then
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begin
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FieldSize:=dsMaxStringSize-1;
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end;
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+
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+ if FieldType=ftUnknown then // if unknown field type encountered, try finding more specific information about the ODBC SQL DataType
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+ begin
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+ SetLength(TypeName,TypeNameDefaultLength); // also garantuees uniqueness
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+
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+ ODBCCheckResult(
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+ SQLColAttribute(ODBCCursor.FSTMTHandle, // statement handle
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+ i, // column number
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+ SQL_DESC_TYPE_NAME, // FieldIdentifier indicating the datasource dependent data type name (useful for diagnostics)
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+ @(TypeName[1]), // default buffer
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+ TypeNameDefaultLength+1, // and its length; we include the #0 terminating any ansistring of Length > 0 in the buffer
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+ @TypeNameLength, // actual type name length
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+ nil // no need for a pointer to return a numeric attribute at
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+ ),
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+ SQL_HANDLE_STMT, ODBCCursor.FSTMTHandle, Format('Could not get datasource dependent type name for column %s.',[ColName])
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+ );
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+ // truncate buffer or make buffer long enough for entire column name (note: the call is the same for both cases!)
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+ SetLength(TypeName,TypeNameLength);
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+ // check whether entire column name was returned
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+ if TypeNameLength>TypeNameDefaultLength then
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+ begin
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+ // request column name with buffer that is long enough
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+ ODBCCheckResult(
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+ SQLColAttribute(ODBCCursor.FSTMTHandle, // statement handle
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+ i, // column number
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+ SQL_DESC_TYPE_NAME, // FieldIdentifier indicating the datasource dependent data type name (useful for diagnostics)
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+ @(TypeName[1]), // buffer
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+ TypeNameLength+1, // buffer size
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+ @TypeNameLength, // actual length
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+ nil), // no need for a pointer to return a numeric attribute at
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+ SQL_HANDLE_STMT, ODBCCursor.FSTMTHandle, Format('Could not get datasource dependent type name for column %s.',[ColName])
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+ );
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+ end;
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+
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+ DatabaseErrorFmt('Column %s has an unknown or unsupported column type. Datasource dependent type name: %s. ODBC SQL data type code: %d.', [ColName, TypeName, DataType]);
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+ end;
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// add FieldDef
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TFieldDef.Create(FieldDefs, ColName, FieldType, FieldSize, False, i);
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@@ -773,6 +881,9 @@ begin
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SQLAllocHandle(SQL_HANDLE_STMT, Connection.FDBCHandle, FSTMTHandle),
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SQL_HANDLE_DBC, Connection.FDBCHandle, 'Could not allocate ODBC Statement handle.'
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);
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+
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+ // allocate FBlobStreams
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+ FBlobStreams:=TList.Create;
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end;
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destructor TODBCCursor.Destroy;
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@@ -780,6 +891,8 @@ var
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Res:SQLRETURN;
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begin
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inherited Destroy;
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+
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+ FBlobStreams.Free;
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if FSTMTHandle<>SQL_INVALID_HANDLE then
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begin
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joost