Changeset 22 for trunk/DbEngines

Timestamp:

Mar 24, 2018, 12:33:48 AM (7 years ago)

Author:

chronos

Message:

• Modified: Tables creation/deletion using SQL syntax for XML backend.

File:

• trunk/DbEngines/UEngineXML.pas (modified) (5 diffs)

trunk/DbEngines/UEngineXML.pas

@@ -30 +30 @@
     procedure LoadFromFile(FileName: string);
     procedure SaveToFile(FileName: string);
+    procedure Expect(var Source: string; Text: string);
+    function CheckNext(var Source: string; Text: string): Boolean;
     function GetNextPart(var Text: string; Separator: string = ' '): string;
   protected
@@ -304 +306 @@
 end;
 
+procedure TDatabaseXML.Expect(var Source: string; Text: string);
+var
+  Found: string;
+begin
+  Found := GetNextPart(Source);
+  if Found <> Text then
+    raise Exception.Create('Expected ' + Text + ' but ' + Found + ' found.');
+end;
+
+function TDatabaseXML.CheckNext(var Source: string; Text: string): Boolean;
+var
+  Found: string;
+  SourceCopy: string;
+begin
+  SourceCopy := Source;
+  Found := GetNextPart(SourceCopy);
+  if Found = Text then begin
+    Source := SourceCopy;
+    Result := True;
+  end else Result := False;
+end;
+
 function TDatabaseXML.GetNextPart(var Text: string; Separator: string = ' '): string;
 begin
@@ -324 +348 @@
   I: Integer;
   F: Integer;
+  Row: TRecord;
+  WhereName: string;
+  WhereValue: string;
+  InsertValues: TStringList;
+  Field: TField;
+  FieldIndex: Integer;
+  NewValue: TValue;
+  ValueIndex: Integer;
 begin
   Command := GetNextPart(Text);
   if Command = 'SELECT' then begin
     Columns := GetNextPart(Text);
-    Command := GetNextPart(Text);
-    if Command = 'FROM' then begin
-      TableName := GetNextPart(Text);
-    end else raise Exception.Create('No table specified with FROM');
+    Expect(Text, 'FROM');
+    TableName := GetNextPart(Text);
     Table := Tables.SearchByName(TableName);
     if Assigned(Table) then begin
@@ -350 +380 @@
     end else raise Exception.Create('Table ' + TableName + ' not found.');
   end else
-  if Command = 'CREATE' then begin
-    Command := GetNextPart(Text);
-    if Command = 'TABLE' then begin
-      TableName := GetNextPart(Text);
+  if Command = 'INSERT' then begin
+    InsertValues := TStringList.Create;
+    Expect(Text, 'INTO');
+    TableName := GetNextPart(Text);
+    Expect(Text, '(');
+    InsertValues.Add(GetNextPart(Text) + InsertValues.NameValueSeparator);
+    while CheckNext(Text, ',') do begin
+      InsertValues.Add(GetNextPart(Text) + InsertValues.NameValueSeparator);
+    end;
+    Expect(Text, ')');
+    Expect(Text, 'VALUES');
+    Expect(Text, '(');
+    ValueIndex := 0;
+    InsertValues.ValueFromIndex[ValueIndex] := GetNextPart(Text);
+    Inc(ValueIndex);
+    while CheckNext(Text, ',') do begin
+      InsertValues.ValueFromIndex[ValueIndex] := GetNextPart(Text);
+      Inc(ValueIndex);
+    end;
+    Expect(Text, ')');
+    if TableName = 'Model' then begin
       Table := TTable.Create;
-      Table.Name := TableName;
+      Table.Name := InsertValues.Values['Name'];
+      Table.Caption := InsertValues.Values['Caption'];
       Table.DbClient := Self;
-      Tables.Add(Table);;
-    end else raise Exception.Create('TABLE keyword expected');
+      Tables.Add(Table);
+    end else begin
+      Table := Tables.SearchByName(TableName);
+      if Assigned(Table) then begin
+        Row := TRecord.Create;
+        Row.Parent := Table;
+        Row.InitValues;
+        for ValueIndex := 0 to InsertValues.Count - 1 do begin
+          Field := Table.Fields.SearchByName(InsertValues.Names[ValueIndex]);
+          FieldIndex := Table.Fields.IndexOf(Field);
+          TValue(Row.Values[FieldIndex]).SetString(InsertValues.ValueFromIndex[ValueIndex]);
+        end;
+        Table.Records.Add(Row);
+      end else raise Exception.Create(Format('Table %s not found', [TableName]));
+    end;
+    InsertValues.Free;
   end else
-  if Command = 'DROP' then begin
-    Command := GetNextPart(Text);
-    if Command = 'TABLE' then begin
-      TableName := GetNextPart(Text);
+  if Command = 'DELETE' then begin
+    Expect(Text, 'FROM');
+    TableName := GetNextPart(Text);
+    if CheckNext(Text, 'WHERE') then begin
+      WhereName := GetNextPart(Text);
+      Command := GetNextPart(Text);
+      if Command = '=' then begin
+        WhereValue := GetNextPart(Text);
+      end else raise Exception.Create('Expression error');
+    end;
+    if TableName = 'Model' then begin
+      Table := Tables.SearchByName(WhereValue);
+      if Assigned(Table) then begin
+        Tables.Remove(Table);
+      end else raise Exception.Create(Format('Table %s not found', [whereValue]));
+    end else begin
       Table := Tables.SearchByName(TableName);
-      if Assigned(Table) then Tables.Remove(Table)
-      else raise Exception.Create('Table ' + TableName + ' not found');
-    end else raise Exception.Create('TABLE keyword expected');
+      if Assigned(Table) then begin
+        Row := Table.Records.SearchByValue(WhereName, WhereValue);
+        if Assigned(Row) then begin
+          Table.Records.Remove(Row);
+        end else raise Exception.Create('Row not found');
+      end else raise Exception.Create(Format('Table %s not found', [TableName]));
+    end;
   end else
     raise Exception.Create('Unsupported SQL command ' + Command);
@@ -380 +458 @@
 begin
   FileName := TDbConnectParamsXml(ConnectProfile.Params).FileName;
+  Tables.DbClient := Self;
   if FileExists(FileName) then
     LoadFromFile(FileName);