new TSqlDbConnectionProperties.EnsureColumnNameUnique property

- by default, result column names won't be checked for name unicity
- it is up to your SQL statement to return genuine columns
- ColumName() lookup will use O(1) brute force, so you should rather use per-index Column*() methods
- force true to have the mORMot 1 compatible behavior, in which column names will be hashed for unicity (so will be slower at execution), but will allow faster ColumnName() lookup

src/db/mormot.db.proxy.pas

@@ -1339,7 +1339,7 @@ procedure TSqlDBProxyStatementAbstract.InternalHeaderProcess(
     for F := 0 to colcount - 1 do
     begin
       FromVarString(Data, colname);
-      prop := fColumn.AddAndMakeUniqueName(colname);
+      prop := AddColumn(colname);
       prop^.ColumnType := TSqlDBFieldType(Data^);
       inc(Data);
       prop^.ColumnValueDBSize := FromVarUInt32(Data);

src/db/mormot.db.rad.pas

@@ -592,14 +592,12 @@ procedure TSqlDBDatasetStatementAbstract.ExecutePrepared;
     begin
       fQuery.Open;
       fCurrentRow := -1;
-      fColumnCount := 0;
-      fColumn.ForceReHash;
+      ClearColumns;
       fColumn.Capacity := fQuery.FieldCount;
       for i := 0 to fQuery.FieldCount - 1 do
       begin
         field := DatasetField(i);
-        with PSqlDBColumnProperty(fColumn.AddAndMakeUniqueName(
-              StringToUtf8(field.FieldName)))^ do
+        with AddColumn(StringToUtf8(field.FieldName))^ do
         begin
           ColumnAttr := PtrUInt(field);
           ColumnType := ColumnTypeNativeToDB(field.DataType);

src/db/mormot.db.raw.sqlite3.pas

@@ -4431,6 +4431,7 @@   TSqlRequest = record
       Expand: boolean = false; aResultCount: PPtrInt = nil;
       MaxMemory: PtrUInt = 512 shl 20; Options: TTextWriterOptions = []): RawUtf8;
     /// Execute one SQL statement step into a JSON object
+    // - has less overhead than ExecuteJson() for a single row of data
     function ExecuteStepJson(aDB: TSqlite3DB; W: TJsonWriter): boolean;
     /// Execute one SQL statement which return the results as a TDocVariant array
     // - if aSql is '', the statement should have been prepared, reset and bound

src/db/mormot.db.sql.ibx.pas

@@ -428,8 +428,7 @@ procedure TSqlDBIbxStatement.Prepare(const aSQL: RawUtf8; ExpectResults: boolean
     tr, {$ifdef UNICODE} Utf8ToString(fSQL) {$else} fSQL {$endif});
   fStatement.SetStaleReferenceChecks(false);
   fStatement.SetRetainInterfaces(true);
-  fColumnCount := 0;
-  fColumn.ReHash;
+  ClearColumns;
   fIbxParams := fStatement.GetSQLParams;
   SetLength(farrParams, fIbxParams.Count);
   for i := 0 to fIbxParams.Count - 1 do
@@ -448,9 +447,8 @@ procedure TSqlDBIbxStatement.Prepare(const aSQL: RawUtf8; ExpectResults: boolean
       fColumnsMeta[i].Scale := fColumnMetaData.getScale;
       fColumnsMeta[i].Subtype := fColumnMetaData.getSubtype;
       name := fColumnMetaData.getName;
-      PSqlDBColumnProperty(fColumn.AddAndMakeUniqueName(
-        // Delphi<2009: already UTF-8 encoded due to controls_cp=CP_UTF8
-        {$ifdef UNICODE} StringToUtf8 {$endif}(name)))^.ColumnType :=
+      AddColumn(// Delphi<2009: already UTF-8 encoded due to controls_cp=CP_UTF8
+        {$ifdef UNICODE}StringToUtf8{$endif}(name))^.ColumnType :=
           IbxSQLTypeToTSqlDBFieldType(fColumnsMeta[i]);
     end;
   end;

src/db/mormot.db.sql.odbc.pas

@@ -639,8 +639,7 @@ procedure TSqlDBOdbcStatement.BindColumns;
         DescribeColW(fStatement, c, Name{%H-}, 256, NameLength, DataType,
           ColumnSize, DecimalDigits, Nullable),
         SQL_HANDLE_STMT, fStatement);
-      with PSqlDBColumnProperty(
-        fColumn.AddAndMakeUniqueName(RawUnicodeToUtf8(Name, NameLength)))^ do
+      with AddColumn(RawUnicodeToUtf8(Name, NameLength))^ do
       begin
         ColumnValueInlined := true;
         ColumnValueDBType := DataType;
@@ -1270,8 +1269,7 @@ procedure TSqlDBOdbcStatement.ReleaseRows;
   begin
     if fStatement <> nil then
       ODBC.CloseCursor(fStatement); // no check needed
-    fColumn.Clear;
-    fColumn.ForceReHash;
+    ClearColumns;
   end;
   inherited ReleaseRows;
 end;

src/db/mormot.db.sql.oracle.pas

@@ -1916,8 +1916,7 @@ procedure TSqlDBOracleStatement.FreeHandles(AfterError: boolean);
   end;
   if fRowBuffer <> nil then
     SetLength(fRowBuffer, 0); // release internal buffer memory
-  if fColumnCount > 0 then
-    fColumn.Clear;
+  ClearColumns;
 end;
 
 function TSqlDBOracleStatement.GetCol(Col: integer; out Column:
@@ -2006,7 +2005,7 @@ procedure TSqlDBOracleStatement.SetColumnsForPreparedStatement;
         FastSetString(aName, oName, oNameLen);
       AttrGet(oHandle, OCI_DTYPE_PARAM, @oType, nil, OCI_ATTR_DATA_TYPE, fError);
       AttrGet(oHandle, OCI_DTYPE_PARAM, @oSize, nil, OCI_ATTR_DATA_SIZE, fError);
-      with PSqlDBColumnProperty(fColumn.AddAndMakeUniqueName(aName))^ do
+      with AddColumn(aName)^ do
       begin
         ColumnValueDBSize := oSize;
         ColumnValueInlined := true;

src/db/mormot.db.sql.pas

@@ -1226,8 +1226,8 @@   TSqlDBConnectionProperties = class
     fDbms: TSqlDBDefinition;
     fBatchSendingAbilities: TSqlDBStatementCRUDs;
     fUseCache, fStoreVoidStringAsNull, fLogSqlStatementOnException,
-      fRollbackOnDisconnect, fReconnectAfterConnectionError,
-      fFilterTableViewSchemaName: boolean;
+    fRollbackOnDisconnect, fReconnectAfterConnectionError,
+    fEnsureColumnNameUnique, fFilterTableViewSchemaName: boolean;
     {$ifndef UNICODE}
     fVariantWideString: boolean;
     {$endif UNICODE}
@@ -1837,6 +1837,15 @@   TSqlDBConnectionProperties = class
     // - is set to TRUE by default
     property RollbackOnDisconnect: boolean
       read fRollbackOnDisconnect write fRollbackOnDisconnect;
+    /// by default, result column names won't be checked for name unicity
+    // - it is up to your SQL statement to return genuine columns
+    // - ColumName() lookup will use O(1) brute force, so you should rather
+    // use per-index Column*() methods
+    // - force true to have the mORMot 1 compatible behavior, in which column
+    // names will be hashed for unicity (so will be slower at execution),
+    // but will allow faster ColumnName() lookup
+    property EnsureColumnNameUnique: boolean
+      read fEnsureColumnNameUnique write fEnsureColumnNameUnique;
     /// defines if '' string values are to be stored as SQL null
     // - by default, '' will be stored as ''
     // - but some DB engines (e.g. Jet or MS SQL) does not allow by default to
@@ -1868,7 +1877,7 @@   TSqlDBConnectionProperties = class
     property VariantStringAsWideString: boolean
       read fVariantWideString write fVariantWideString;
     {$endif UNICODE}
-    /// SQL statements what will be executed for each new connection
+    /// SQL statements what will be executed for each new connection, as typical
     // usage scenarios examples:
     // - Oracle: force case-insensitive like
     // $  ['ALTER SESSION SET NLS_COMP=LINGUISTIC', 'ALTER SESSION SET NLS_SORT=BINARY_CI']
@@ -2914,6 +2923,8 @@   TSqlDBStatementWithParamsAndColumns = class(TSqlDBStatementWithParams)
   protected
     fColumns: TSqlDBColumnPropertyDynArray;
     fColumn: TDynArrayHashed;
+    procedure ClearColumns;
+    function AddColumn(const ColName: RawUtf8): PSqlDBColumnProperty;
   public
     /// create a statement instance
     // - this overridden version will initialize the internal fColumn* fields
@@ -3573,8 +3584,8 @@ function TSqlDBConnectionProperties.NewThreadSafeStatement: TSqlDBStatement;
   result := ThreadSafeConnection.NewStatement;
 end;
 
-function TSqlDBConnectionProperties.NewThreadSafeStatementPrepared(const aSql:
-  RawUtf8; ExpectResults, RaiseExceptionOnError: boolean): ISqlDBStatement;
+function TSqlDBConnectionProperties.NewThreadSafeStatementPrepared(
+  const aSql: RawUtf8; ExpectResults, RaiseExceptionOnError: boolean): ISqlDBStatement;
 begin
   result := ThreadSafeConnection.NewStatementPrepared(
     aSql, ExpectResults, RaiseExceptionOnError);
@@ -8081,14 +8092,52 @@ constructor TSqlDBStatementWithParamsAndColumns.Create(
   aConnection: TSqlDBConnection);
 begin
   inherited Create(aConnection);
-  fColumn.InitSpecific(TypeInfo(TSqlDBColumnPropertyDynArray),
-    fColumns, ptRawUtf8, @fColumnCount, {caseinsens=}true);
+  if aConnection.Properties.EnsureColumnNameUnique then
+    fColumn.InitSpecific(TypeInfo(TSqlDBColumnPropertyDynArray),
+      fColumns, ptRawUtf8, @fColumnCount, {caseinsens=}true)
+  else
+    PDynArray(@fColumn)^.Init(TypeInfo(TSqlDBColumnPropertyDynArray),
+      fColumns, @fColumnCount); // no hash index created nor unicity check
+end;
+
+procedure TSqlDBStatementWithParamsAndColumns.ClearColumns;
+begin
+  if fColumnCount = 0 then
+    exit;
+  fColumn.Clear;
+  if fConnection.Properties.EnsureColumnNameUnique then
+    fColumn.ForceReHash;
+end;
+
+function TSqlDBStatementWithParamsAndColumns.AddColumn(
+  const ColName: RawUtf8): PSqlDBColumnProperty;
+begin
+  if fConnection.Properties.EnsureColumnNameUnique then
+    result := fColumn.AddAndMakeUniqueName(ColName)
+  else
+  begin
+    result := PDynArray(@fColumn)^.NewPtr;
+    result^.ColumnName := ColName;
+  end;
 end;
 
 function TSqlDBStatementWithParamsAndColumns.ColumnIndex(
   const aColumnName: RawUtf8): integer;
+var
+  c: PSqlDBColumnProperty;
 begin
-  result := fColumn.FindHashed(aColumnName);
+  if fConnection.Properties.EnsureColumnNameUnique then
+    result := fColumn.FindHashed(aColumnName)
+  else
+  begin
+    c := pointer(fColumns);
+    for result := 0 to fColumnCount - 1 do
+      if IdemPropNameU(aColumnName, c^.ColumnName) then
+        exit // brute force O(n) case insensitive check
+      else
+        inc(c);
+    result := -1
+  end;
 end;
 
 function TSqlDBStatementWithParamsAndColumns.ColumnName(Col: integer): RawUtf8;

src/db/mormot.db.sql.postgres.pas

@@ -526,15 +526,16 @@ procedure TSqlDBPostgresStatement.BindColumns;
 var
   nCols, c: integer;
   cName: RawUtf8;
+  p: PUtf8Char;
 begin
-  fColumn.Clear;
-  fColumn.ForceReHash;
+  ClearColumns;
   nCols := PQ.nfields(fRes);
   fColumn.Capacity := nCols;
   for c := 0 to nCols - 1 do
   begin
-    cName := PQ.fname(fRes, c);
-    with PSqlDBColumnProperty(fColumn.AddAndMakeUniqueName(cName))^ do
+    p := PQ.fname(fRes, c);
+    FastSetString(cName, p, StrLen(p));
+    with AddColumn(cName)^ do
     begin
       ColumnAttr := PQ.ftype(fRes, c);
       ColumnType := TSqlDBPostgresConnectionProperties(Connection.Properties).

src/db/mormot.db.sql.zeos.pas

@@ -1137,8 +1137,7 @@ procedure TSqlDBZeosStatement.ExecutePrepared;
     // 2. Execute query
     if fExpectResults then
     begin
-      fColumnCount := 0;
-      fColumn.ForceReHash;
+      ClearColumns;
       fCurrentRow := -1;
       fResultSet := fStatement.ExecuteQueryPrepared;
       if fResultSet = nil then
@@ -1158,9 +1157,8 @@ procedure TSqlDBZeosStatement.ExecutePrepared;
           name := fResultInfo.GetColumnLabel(i + FirstDbcIndex);
           if name = '' then
             name := fResultInfo.GetColumnName(i + FirstDbcIndex);
-          PSqlDBColumnProperty(fColumn.AddAndMakeUniqueName(
-            // Delphi<2009: already UTF-8 encoded due to controls_cp=CP_UTF8
-            {$ifdef UNICODE}StringToUtf8{$endif}(name)))^.ColumnType :=
+          AddColumn(// Delphi<2009: already UTF-8 encoded due to controls_cp=CP_UTF8
+            {$ifdef UNICODE}StringToUtf8{$endif}(name))^.ColumnType :=
               Props.TZSQLTypeToTSqlDBFieldType(fResultInfo.GetColumnType(i + FirstDbcIndex));
         end;
       end;

src/mormot.commit.inc

@@ -1 +1 @@
-'2.0.3819'
+'2.0.3820'

test/test.orm.sqlite3.pas

@@ -2068,8 +2068,8 @@ procedure TTestSQLite3Engine._TOrmTableJson;
     if JS <> '' then // avoid memory leak
       with TOrmTableDB.Create(Demo, [], Req, {expand=}true) do
       try
-        check(RowCount = J.RowCount);
-        check(FieldCount = J.FieldCount);
+        checkEqual(RowCount, J.RowCount);
+        checkEqual(FieldCount, J.FieldCount);
         SetFieldType('YearOfBirth', oftModTime);
         for aR := 0 to RowCount do
           for aF := 0 to FieldCount - 1 do