/// SQLite3 direct access classes to be used with our SynDB architecture
// - this unit is a part of the freeware Synopse framework,
// licensed under a MPL/GPL/LGPL tri-license; version 1.18
unit SynDBSQLite3;

{
    This file is part of Synopse framework.

    Synopse framework. Copyright (c) Arnaud Bouchez
      Synopse Informatique - https://synopse.info

  *** BEGIN LICENSE BLOCK *****
  Version: MPL 1.1/GPL 2.0/LGPL 2.1

  The contents of this file are subject to the Mozilla Public License Version
  1.1 (the "License"); you may not use this file except in compliance with
  the License. You may obtain a copy of the License at
  http://www.mozilla.org/MPL

  Software distributed under the License is distributed on an "AS IS" basis,
  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  for the specific language governing rights and limitations under the License.

  The Original Code is Synopse mORMot framework.

  The Initial Developer of the Original Code is Arnaud Bouchez.

  Portions created by the Initial Developer are Copyright (c)
  the Initial Developer. All Rights Reserved.

  Contributor(s):

  Alternatively, the contents of this file may be used under the terms of
  either the GNU General Public License Version 2 or later (the "GPL"), or
  the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  in which case the provisions of the GPL or the LGPL are applicable instead
  of those above. If you wish to allow use of your version of this file only
  under the terms of either the GPL or the LGPL, and not to allow others to
  use your version of this file under the terms of the MPL, indicate your
  decision by deleting the provisions above and replace them with the notice
  and other provisions required by the GPL or the LGPL. If you do not delete
  the provisions above, a recipient may use your version of this file under
  the terms of any one of the MPL, the GPL or the LGPL.

  ***** END LICENSE BLOCK *****

}

{$I Synopse.inc} // define HASINLINE CPU32 CPU64 OWNNORMTOUPPER

interface

uses
  {$ifdef MSWINDOWS}
  Windows,
  {$else}
  {$ifdef FPC}
  SynFPCLinux,
  {$else}
  {$ifdef KYLIX3}
  Types,
  LibC,
  SynKylix,
  {$endif}
  {$endif}
  {$endif}
  SysUtils,
  {$ifndef DELPHI5OROLDER}
  Variants,
  {$endif}
  Classes,
  {$ifndef LVCL}
  Contnrs,
  {$endif}
  SynCommons,
  SynLog,
  SynSQLite3,
  SynTable,
  SynDB;

{ -------------- SQlite3 database engine native connection  }

type
  /// will implement properties shared by the SQLite3 engine
  TSQLDBSQLite3ConnectionProperties = class(TSQLDBConnectionProperties)
  private
    fUseMormotCollations: boolean;
    fExistingDB: TSQLDatabase;
    procedure SetUseMormotCollations(const Value: boolean);
    function GetMainDB: TSQLDataBase;
  protected
    /// initialize fForeignKeys content with all foreign keys of this DB
    // - used by GetForeignKey method
    procedure GetForeignKeys; override;
  public
    /// initialize access to a SQLite3 engine with some properties
    // - only used parameter is aServerName, which should point to the SQLite3
    // database file to be opened (one will be created if none exists)
    // - if specified, the password will be used to cypher this file on disk
    // (the main SQLite3 database file is encrypted, not the wal file during run);
    // the password may be a JSON-serialized TSynSignerParams object, or will use
    // AES-OFB-128 after SHAKE_128 with rounds=1000 and a fixed salt on plain password text
    // - other parameters (DataBaseName, UserID) are ignored
    constructor Create(const aServerName, aDatabaseName, aUserID, aPassWord: RawUTF8); overload; override;
    /// initialize access to an existing SQLite3 engine
    // - this overloaded constructor allows to access via SynDB methods to an
    // existing SQLite3 database, e.g. TSQLRestServerDB.DB (from mORMotSQLite3.pas)
    constructor Create(aDB: TSQLDatabase); reintroduce; overload;
    /// create a new connection
    // - call this method if the shared MainConnection is not enough (e.g. for
    // multi-thread access)
    // - the caller is responsible of freeing this instance
    function NewConnection: TSQLDBConnection; override;
    /// direct access to the main SQlite3 DB instance
    // - can be used to tune directly the database properties
    property MainSQLite3DB: TSQLDataBase read GetMainDB;
  published
    /// TRUE if you want the SQL creation fields to use mORMot collation
    // - default value is TRUE for use within the mORMot framework, to use
    // dedicated UTF-8 collation and full Unicode support, and Iso8601 handling
    // - when set to FALSE, SQLCreate() method will return standard ASCII
    // SQLite collations for TEXT: it will make interaction with other programs
    // more compatible, at database file level
    property UseMormotCollations: boolean read fUseMormotCollations write SetUseMormotCollations;
  end;

  /// implements a direct connection to the SQLite3 engine
  TSQLDBSQLite3Connection = class(TSQLDBConnection)
  protected
    fDB: TSQLDataBase;
    function GetSynchronous: TSQLSynchronousMode;
    procedure SetSynchronous(Value: TSQLSynchronousMode);
    procedure SetLockingMode(Value: TSQLLockingMode);
    function GetLockingMode: TSQLLockingMode;
  public
    /// connect to the SQLite3 engine, i.e. create the DB instance
    // - should raise an Exception on error
    procedure Connect; override;
    /// stop connection to the SQLite3 engine, i.e. release the DB instance
    // - should raise an Exception on error
    procedure Disconnect; override;
    /// return TRUE if Connect has been already successfully called
    function IsConnected: boolean; override;
    /// initialize a new SQL query statement for the given connection
    // - the caller should free the instance after use
    function NewStatement: TSQLDBStatement; override;
    /// begin a Transaction for this connection
    // - current implementation do not support nested transaction with those
    // methods: exception will be raised in such case
    procedure StartTransaction; override;
    /// commit changes of a Transaction for this connection
    // - StartTransaction method must have been called before
    procedure Commit; override;
    /// discard changes of a Transaction for this connection
    // - StartTransaction method must have been called before
    procedure Rollback; override;
    /// the associated SQLite3 DB instance
    // - assigned to not nil after successfull connection
    property DB: TSQLDataBase read fDB;
    /// query or change the SQlite3 file-based syncrhonization mode, i.e. the
    // way it waits for the data to be flushed on hard drive
    // - default smFull is very slow, but achieve 100% ACID behavior
    // - smNormal is faster, and safe until a catastrophic hardware failure occurs
    // - smOff is the fastest, data should be safe if the application crashes,
    // but database file may be corrupted in case of failure at the wrong time
    property Synchronous: TSQLSynchronousMode read GetSynchronous write SetSynchronous;
    /// query or change the SQlite3 file-based locking mode, i.e. the
    // way it locks the file
    // - default lmNormal is ACID and safe
    // - lmExclusive gives better performance in case of a number of write
    // transactions, so can be used to release a mORMot server power: but you
    // won't be able to access the database file from outside the process (like
    // a "normal" database engine)
    property LockingMode: TSQLLockingMode read GetLockingMode write SetLockingMode;
  end;

  /// implements a statement using the SQLite3 engine
  TSQLDBSQLite3Statement = class(TSQLDBStatement)
  protected
    fStatement: TSQLRequest;
    fShouldLogSQL: boolean; // sllSQL in SynDBLog.Level -> set fLogSQLValues[]
    fLogSQLValues: TVariantDynArray;
    fUpdateCount: integer;
    // retrieve the inlined value of a given parameter, e.g. 1 or 'name'
    procedure AddParamValueAsText(Param: integer; Dest: TTextWriter;
      MaxCharCount: integer); override;
  public
    /// create a SQLite3 statement instance, from an existing SQLite3 connection
    // - the Execute method can be called once per TSQLDBSQLite3Statement instance,
    // but you can use the Prepare once followed by several ExecutePrepared methods
    // - if the supplied connection is not of TOleDBConnection type, will raise
    // an exception
    constructor Create(aConnection: TSQLDBConnection); override;
    /// release all associated memory and SQLite3 handles
    destructor Destroy; override;

    /// bind a NULL value to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindNull(Param: Integer; IO: TSQLDBParamInOutType=paramIn;
      BoundType: TSQLDBFieldType=ftNull); override;
    /// bind an integer value to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure Bind(Param: Integer; Value: Int64;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a double value to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure Bind(Param: Integer; Value: double;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a TDateTime value to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindDateTime(Param: Integer; Value: TDateTime;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a currency value to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindCurrency(Param: Integer; Value: currency;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a UTF-8 encoded string to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindTextU(Param: Integer; const Value: RawUTF8;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a UTF-8 encoded buffer text (#0 ended) to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindTextP(Param: Integer; Value: PUTF8Char;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a UTF-8 encoded string to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindTextS(Param: Integer; const Value: string;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a UTF-8 encoded string to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindTextW(Param: Integer; const Value: WideString;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a Blob buffer to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindBlob(Param: Integer; Data: pointer; Size: integer;
      IO: TSQLDBParamInOutType=paramIn); overload; override;
    /// bind a Blob buffer to a parameter
    // - the leftmost SQL parameter has an index of 1
    procedure BindBlob(Param: Integer; const Data: RawByteString;
      IO: TSQLDBParamInOutType=paramIn); overload; override;

    /// Prepare an UTF-8 encoded SQL statement
    // - parameters marked as ? will be bound later, before ExecutePrepared call
    // - if ExpectResults is TRUE, then Step() and Column*() methods are available
    // to retrieve the data rows
    // - raise an ESQLDBException on any error
    procedure Prepare(const aSQL: RawUTF8; ExpectResults: Boolean=false); overload; override;
    /// Execute a prepared SQL statement
    // - parameters marked as ? should have been already bound with Bind*() functions
    // - raise an ESQLDBException on any error
    procedure ExecutePrepared; override;
    /// gets a number of updates made by latest executed statement
    function UpdateCount: integer; override;

    /// After a statement has been prepared via Prepare() + ExecutePrepared() or
    // Execute(), this method must be called one or more times to evaluate it
    // - you shall call this method before calling any Column*() methods
    // - return TRUE on success, with data ready to be retrieved by Column*()
    // - return FALSE if no more row is available (e.g. if the SQL statement
    // is not a SELECT but an UPDATE or INSERT command)
    // - access the first or next row of data from the SQL Statement result:
    // if SeekFirst is TRUE, will put the cursor on the first row of results,
    // otherwise, it will fetch one row of data, to be called within a loop
    // - raise an ESQLite3Exception exception on any error
    function Step(SeekFirst: boolean=false): boolean; override;
    /// finalize the cursor
    procedure ReleaseRows; override;
    /// retrieve a column name of the current Row
    // - Columns numeration (i.e. Col value) starts with 0
    // - it's up to the implementation to ensure than all column names are unique
    function ColumnName(Col: integer): RawUTF8; override;
    /// returns the Column index of a given Column name
    // - Columns numeration (i.e. Col value) starts with 0
    // - returns -1 if the Column name is not found (via case insensitive search)
    function ColumnIndex(const aColumnName: RawUTF8): integer; override;
    /// the Column type of the current Row
    // - ftCurrency type should be handled specificaly, for faster process and
    // avoid any rounding issue, since currency is a standard OleDB type
    function ColumnType(Col: integer; FieldSize: PInteger=nil): TSQLDBFieldType; override;
    /// Reset the previous prepared statement
    procedure Reset; override;
    /// returns TRUE if the column contains NULL
    function ColumnNull(Col: integer): boolean; override;
    /// return a Column integer value of the current Row, first Col is 0
    function ColumnInt(Col: integer): Int64; override;
    /// return a Column floating point value of the current Row, first Col is 0
    function ColumnDouble(Col: integer): double; override;
    /// return a Column floating point value of the current Row, first Col is 0
    function ColumnDateTime(Col: integer): TDateTime; override;
    /// return a Column currency value of the current Row, first Col is 0
    // - should retrieve directly the 64 bit Currency content, to avoid
    // any rounding/conversion error from floating-point types
    function ColumnCurrency(Col: integer): currency; override;
    /// return a Column UTF-8 encoded text value of the current Row, first Col is 0
    function ColumnUTF8(Col: integer): RawUTF8; override;
    /// return a Column as a blob value of the current Row, first Col is 0
    // - ColumnBlob() will return the binary content of the field is was not ftBlob,
    // e.g. a 8 bytes RawByteString for a vtInt64/vtDouble/vtDate/vtCurrency,
    // or a direct mapping of the RawUnicode
    function ColumnBlob(Col: integer): RawByteString; override;
    /// append all columns values of the current Row to a JSON stream
    // - will use WR.Expand to guess the expected output format
    // - fast overridden implementation with no temporary variable
    // - BLOB field value is saved as Base64, in the '"\uFFF0base64encodedbinary"
    // format and contains true BLOB data
    procedure ColumnsToJSON(WR: TJSONWriter); override;
  end;

/// direct export of a DB statement rows into a SQLite3 database
// - the corresponding table will be created within the specified DB file
function RowsToSQLite3(const Dest: TFileName; const TableName: RawUTF8;
  Rows: TSQLDBStatement; UseMormotCollations: boolean): integer;


implementation


function RowsToSQLite3(const Dest: TFileName; const TableName: RawUTF8;
  Rows: TSQLDBStatement; UseMormotCollations: boolean): integer;
var DB: TSQLDBSQLite3ConnectionProperties;
    Conn: TSQLDBSQLite3Connection;
begin
  result := 0;
  if (Dest='') or (Rows=nil) or (Rows.ColumnCount=0) then
    exit;
  // we do not call DeleteFile(Dest) since DB may be completed on purpose
  DB := TSQLDBSQLite3ConnectionProperties.Create(StringToUTF8(Dest),'','','');
  try
    DB.UseMormotCollations := UseMormotCollations;
    Conn := DB.MainConnection as TSQLDBSQLite3Connection;
    Conn.Connect;
    result := Conn.NewTableFromRows(TableName,Rows,true);
    Conn.Disconnect;
  finally
    DB.Free;
  end;
end;

{ TSQLDBSQLite3ConnectionProperties }

procedure TSQLDBSQLite3ConnectionProperties.SetUseMormotCollations(const Value: boolean);
const SQLITE3_FIELDS: array[boolean] of TSQLDBFieldTypeDefinition = (
  (' INTEGER',' TEXT',' INTEGER',' FLOAT',' FLOAT',' TEXT',' TEXT',' BLOB'),
  (' INTEGER',' TEXT COLLATE SYSTEMNOCASE',' INTEGER',' FLOAT',' FLOAT',
   ' TEXT COLLATE ISO8601',' TEXT COLLATE SYSTEMNOCASE',' BLOB'));
begin
  fUseMormotCollations := Value;
  fSQLCreateField := SQLITE3_FIELDS[Value];
end;

function TSQLDBSQLite3ConnectionProperties.GetMainDB: TSQLDataBase;
begin
  if self=nil then
    result := nil else
    if fExistingDB<>nil then
      result := fExistingDB else
      with MainConnection as TSQLDBSQLite3Connection do begin
        if not IsConnected then
          Connect; // we expect the SQLite3 instance to be created if needed
        result := DB;
      end;
end;

constructor TSQLDBSQLite3ConnectionProperties.Create(const aServerName,
  aDatabaseName, aUserID, aPassWord: RawUTF8);
begin
  fDBMS := dSQLite;
  inherited Create(aServerName,aDatabaseName,aUserID,aPassWord);
  UseMormotCollations := true;
end;

type
  TSQLDatabaseHook = class(TSQLDatabase); // to access fPassword

constructor TSQLDBSQLite3ConnectionProperties.Create(aDB: TSQLDatabase);
begin
  if aDB=nil then
    raise ESQLDBException.CreateUTF8('%.Create(DB=nil)',[self]);
  fExistingDB := aDB;
  Create('',StringToUTF8(aDB.FileName),'',TSQLDatabaseHook(aDB).fPassword);
end;

procedure TSQLDBSQLite3ConnectionProperties.GetForeignKeys;
begin
  // do nothing (yet)
end;

function TSQLDBSQLite3ConnectionProperties.NewConnection: TSQLDBConnection;
begin
  result := TSQLDBSQLite3Connection.Create(self);
end;


{ TSQLDBSQLite3Connection }

procedure TSQLDBSQLite3Connection.Commit;
begin
  inherited Commit;
  try
    fDB.Commit;
  except
    inc(fTransactionCount); // the transaction is still active
    raise;
  end;
end;

procedure TSQLDBSQLite3Connection.Connect;
var Log: ISynLog;
begin
  Log := SynDBLog.Enter;
  Disconnect; // force fTrans=fError=fServer=fContext=nil
  fDB := (Properties as TSQLDBSQLite3ConnectionProperties).fExistingDB;
  if fDB=nil then
    fDB := TSQLDatabase.Create(UTF8ToString(Properties.ServerName),Properties.PassWord);
  //fDB.SetWalMode(true); // slower INSERT in WAL mode for huge number of rows
  inherited Connect; // notify any re-connection
end;

procedure TSQLDBSQLite3Connection.Disconnect;
begin
  inherited Disconnect; // flush any cached statement
  if (Properties as TSQLDBSQLite3ConnectionProperties).fExistingDB=fDB then
    fDB := nil else
    FreeAndNil(fDB);
end;

function TSQLDBSQLite3Connection.GetLockingMode: TSQLLockingMode;
begin
  if IsConnected then
    result := fDB.LockingMode else
    result := lmNormal;
end;

function TSQLDBSQLite3Connection.GetSynchronous: TSQLSynchronousMode;
begin
  if IsConnected then
    result := fDB.Synchronous else
    result := smFull;
end;

function TSQLDBSQLite3Connection.IsConnected: boolean;
begin
  result := fDB<>nil;
end;

function TSQLDBSQLite3Connection.NewStatement: TSQLDBStatement;
begin
  result := TSQLDBSQLite3Statement.Create(self);
end;

procedure TSQLDBSQLite3Connection.Rollback;
begin
  inherited;
  fDB.RollBack;
end;

procedure TSQLDBSQLite3Connection.SetLockingMode(Value: TSQLLockingMode);
begin
  if self=nil then exit;
  if fDB=nil then
    Connect;
  fDB.LockingMode := Value;
end;

procedure TSQLDBSQLite3Connection.SetSynchronous(Value: TSQLSynchronousMode);
begin
  if self=nil then exit;
  if fDB=nil then
    Connect;
  fDB.Synchronous := Value;
end;

procedure TSQLDBSQLite3Connection.StartTransaction;
begin
  inherited;
  fDB.TransactionBegin;
end;


{ TSQLDBSQLite3Statement }

procedure TSQLDBSQLite3Statement.Bind(Param: Integer; Value: double;
  IO: TSQLDBParamInOutType);
begin
  if fShouldLogSQL and (cardinal(Param-1)<cardinal(length(fLogSQLValues))) then
    fLogSQLValues[Param-1] := Value;
  fStatement.Bind(Param,Value);
end;

procedure TSQLDBSQLite3Statement.Bind(Param: Integer; Value: Int64;
  IO: TSQLDBParamInOutType);
begin
  if fShouldLogSQL and (cardinal(Param-1)<cardinal(length(fLogSQLValues))) then
    fLogSQLValues[Param-1] := Value;
  fStatement.Bind(Param,Value);
end;

procedure TSQLDBSQLite3Statement.BindBlob(Param: Integer; Data: pointer;
  Size: integer; IO: TSQLDBParamInOutType);
begin
  if fShouldLogSQL and (cardinal(Param-1)<cardinal(length(fLogSQLValues))) then
    fLogSQLValues[Param-1] := Size;
  fStatement.Bind(Param,Data,Size);
end;

procedure TSQLDBSQLite3Statement.BindBlob(Param: Integer;
  const Data: RawByteString; IO: TSQLDBParamInOutType);
begin
  if fShouldLogSQL and (cardinal(Param-1)<cardinal(length(fLogSQLValues))) then
    fLogSQLValues[Param-1] := length(Data);
  fStatement.BindBlob(Param,Data);
end;

procedure TSQLDBSQLite3Statement.BindCurrency(Param: Integer;
  Value: currency; IO: TSQLDBParamInOutType);
begin
  if fShouldLogSQL and (cardinal(Param-1)<cardinal(length(fLogSQLValues))) then
    fLogSQLValues[Param-1] := Value;
  fStatement.Bind(Param,Value);
end;

procedure TSQLDBSQLite3Statement.BindDateTime(Param: Integer;
  Value: TDateTime; IO: TSQLDBParamInOutType);
begin // see http://www.sqlite.org/lang_datefunc.html
  BindTextU(Param,DateTimeToIso8601Text(Value,'T'));
end;

procedure TSQLDBSQLite3Statement.BindNull(Param: Integer;
  IO: TSQLDBParamInOutType; BoundType: TSQLDBFieldType);
begin
  fStatement.BindNull(Param);
end;

const
  NULCHAR: AnsiChar = #0;

procedure TSQLDBSQLite3Statement.BindTextP(Param: Integer;
  Value: PUTF8Char; IO: TSQLDBParamInOutType);
var V: RawUTF8;
begin
  FastSetString(V,Value,StrLen(Value));
  BindTextU(Param,V);
end;

procedure TSQLDBSQLite3Statement.BindTextS(Param: Integer;
  const Value: string; IO: TSQLDBParamInOutType);
begin
  BindTextU(Param,StringToUTF8(Value));
end;

procedure TSQLDBSQLite3Statement.BindTextU(Param: Integer;
  const Value: RawUTF8; IO: TSQLDBParamInOutType);
begin
  if fShouldLogSQL and (cardinal(Param-1)<cardinal(length(fLogSQLValues))) then
    RawUTF8ToVariant(Value,fLogSQLValues[Param-1]);
  fStatement.Bind(Param,Value);
end;

procedure TSQLDBSQLite3Statement.BindTextW(Param: Integer;
  const Value: WideString; IO: TSQLDBParamInOutType);
begin
  BindTextU(Param,WideStringToUTF8(Value));
end;

function TSQLDBSQLite3Statement.ColumnBlob(Col: integer): RawByteString;
begin
  result := fStatement.FieldBlob(Col);
end;

function TSQLDBSQLite3Statement.ColumnCurrency(Col: integer): currency;
begin
  result := fStatement.FieldDouble(Col);
end;

function TSQLDBSQLite3Statement.ColumnDateTime(Col: integer): TDateTime;
begin
  case ColumnType(Col) of
  ftUTF8:
    result := Iso8601ToDateTime(fStatement.FieldUTF8(Col));
  ftInt64:
    result := TimeLogToDateTime(fStatement.FieldInt(Col));
  else result := 0;
  end;
end;

function TSQLDBSQLite3Statement.ColumnDouble(Col: integer): double;
begin
  result := fStatement.FieldDouble(Col);
end;

function TSQLDBSQLite3Statement.ColumnIndex(const aColumnName: RawUTF8): integer;
begin
  result := fStatement.FieldIndex(aColumnName);
end;

function TSQLDBSQLite3Statement.ColumnInt(Col: integer): Int64;
begin
  result := fStatement.FieldInt(Col);
end;

function TSQLDBSQLite3Statement.ColumnName(Col: integer): RawUTF8;
begin
  result := fStatement.FieldName(Col);
end;

function TSQLDBSQLite3Statement.ColumnNull(Col: integer): boolean;
begin
  result := fStatement.FieldNull(Col);
end;

procedure TSQLDBSQLite3Statement.ColumnsToJSON(WR: TJSONWriter);
begin
  fStatement.FieldsToJSON(WR,fForceBlobAsNull);
end;

function TSQLDBSQLite3Statement.ColumnType(Col: integer; FieldSize: PInteger=nil): TSQLDBFieldType;
begin
  if fCurrentRow<=0 then // before any TSQLDBSQLite3Statement.Step call
    result := fConnection.Properties.ColumnTypeNativeToDB(
      fStatement.FieldDeclaredType(Col),8) else
    case fStatement.FieldType(Col) of
    SQLITE_NULL:    result := ftNull;
    SQLITE_INTEGER: result := ftInt64;
    SQLITE_FLOAT:   result := ftDouble;
    SQLITE_TEXT:    result := ftUTF8;
    SQLITE_BLOB:    result := ftBlob;
    else            result := ftUnknown;
    end;
  if FieldSize<>nil then
    FieldSize^ := 0; // no column size in SQLite3
end;

function TSQLDBSQLite3Statement.ColumnUTF8(Col: integer): RawUTF8;
begin
  result := fStatement.FieldUTF8(Col);
end;

constructor TSQLDBSQLite3Statement.Create(aConnection: TSQLDBConnection);
begin
  if not aConnection.InheritsFrom(TSQLDBSQLite3Connection) then
    raise ESQLDBException.CreateUTF8('%.Create(%)',[self,aConnection]);
  inherited Create(aConnection);
  if (SynDBLog<>nil) and (sllSQL in SynDBLog.Family.Level) then
    fShouldLogSQL := true;
end;

destructor TSQLDBSQLite3Statement.Destroy;
begin
  try
    fStatement.Close; // release statement
  finally
    inherited Destroy;
  end;
end;

procedure TSQLDBSQLite3Statement.ExecutePrepared;
var DB: TSQLDataBase;
begin
  fCurrentRow := 0; // mark cursor on the first row
  inherited ExecutePrepared; // set fConnection.fLastAccessTicks
  DB := TSQLDBSQLite3Connection(Connection).DB;
  if fExpectResults then
    exit; // execution done in Step()
  if fShouldLogSQL then
    SQLLogBegin(sllSQL);
  try  // INSERT/UPDATE/DELETE (i.e. not SELECT) -> try to execute directly now
    repeat // Execute all steps of the first statement
    until fStatement.Step<>SQLITE_ROW;
    fUpdateCount := DB.LastChangeCount;
  finally
    if fShouldLogSQL then
      SQLLogEnd;
  end;
end;

function TSQLDBSQLite3Statement.UpdateCount: integer;
begin
  result := fUpdateCount;
end;

procedure TSQLDBSQLite3Statement.AddParamValueAsText(Param: integer;
  Dest: TTextWriter; MaxCharCount: integer);
var v: PVarData;
begin
  dec(Param);
  if fShouldLogSQL and (cardinal(Param)<cardinal(length(fLogSQLValues))) then begin
    v := @fLogSQLValues[Param];
    if v^.vtype=varString then
      Dest.AddQuotedStr(v^.VAny,'''',MaxCharCount) else
      Dest.AddVariant(PVariant(v)^);
  end;
end;

procedure TSQLDBSQLite3Statement.Prepare(const aSQL: RawUTF8;
  ExpectResults: Boolean);
begin
  if fShouldLogSQL then
    SQLLogBegin(sllDB);
  inherited Prepare(aSQL,ExpectResults); // set fSQL + Connect if necessary
  fStatement.Prepare(TSQLDBSQLite3Connection(Connection).fDB.DB,aSQL);
  fColumnCount := fStatement.FieldCount;
  if fShouldLogSQL then begin
    fParamCount := fStatement.ParamCount;
    SetLength(fLogSQLValues,fParamCount);
    SQLLogEnd(' %',[TSQLDBSQLite3Connection(Connection).fDB.FileNameWithoutPath]);
  end;
end;

procedure TSQLDBSQLite3Statement.Reset;
begin
  fStatement.Reset;
  fUpdateCount := 0;
  // fStatement.BindReset; // slow down the process, and is not mandatory
  ReleaseRows;
  SetLength(fLogSQLValues,fParamCount);
  inherited Reset;
end;

procedure TSQLDBSQLite3Statement.ReleaseRows;
begin
  VariantDynArrayClear(fLogSQLValues);
  inherited ReleaseRows;
end;

function TSQLDBSQLite3Statement.Step(SeekFirst: boolean): boolean;
begin
  if SeekFirst then begin
    if fCurrentRow>0 then
      raise ESQLDBException.CreateUTF8('%.Step(SeekFirst=true) not implemented',[self]);
    fCurrentRow := 0;
    //fStatement.Reset;
  end;
  try
    result := fStatement.Step=SQLITE_ROW;
  except
    on E: Exception do begin
      if fShouldLogSQL then
        SynDBLog.Add.Log(sllError,'Error % on % for [%] as [%]',
          [E,TSQLDBSQLite3Connection(Connection).DB.FileNameWithoutPath,SQL,
           SQLWithInlinedParams],self);
      raise;
    end;
  end;
  if result then begin
    inc(fTotalRowsRetrieved);
    inc(fCurrentRow);
  end else
    fCurrentRow := 0;
end;

initialization
  TSQLDBSQLite3ConnectionProperties.RegisterClassNameForDefinition;
end.