Question

我想在编写长原始数据时修复zeoslib错误错误描述：

Memo1.Lines.LoadFromFile('c:\t\ZDbcMetadata.pas'); // file size ~ 170Kb
ZQuery1.SQL.Text := 'insert into t1(id, b) values(10, :p1)';
ZQuery1.Params[0].AsBlob := Memo1.Lines.Text;
ZQuery1.ExecSQL;

问题是只有前2000个字节加载到表中

在OCI zeos代码中的

是这样的：

  var
    sql: string;
    Handle: POCIStmt;
    ErrorHandle: POCIError;
    conn: IZOracleConnection;
    FPlainDriver: IZOraclePlainDriver;
    BindHandle, buff: Pointer;
    Status,buflen: integer;
    lob: POCILobLocator;
  begin
    sql := 'insert into t1(id, b) values(10, :p1)';
    conn := ZConnection1.DbcConnection as IZOracleConnection;
    FPlainDriver := conn.GetPlainDriver;

    with TFileStream.Create('c:\t\ZDbcMetadata.pas', fmOpenRead or fmShareDenyNone) do
    begin
      buflen := Size;
      GetMem(buff, buflen);
      ReadBuffer(buff^, buflen);
      Free;
    end;

    AllocateOracleStatementHandles(FPlainDriver, conn, Handle, ErrorHandle);
    try
      PrepareOracleStatement(FPlainDriver, sql, Handle, ErrorHandle);

      Status := FPlainDriver.DescriptorAlloc(conn.GetConnectionHandle, lob,
        OCI_DTYPE_LOB, 0, nil);
      CheckOracleError(FPlainDriver, conn.GetErrorHandle,
        Status, lcOther, 'Open Large Object');

      Status := FPlainDriver.LobCreateTemporary(conn.GetContextHandle,
        conn.GetErrorHandle, lob, OCI_DEFAULT, OCI_DEFAULT,
        OCI_TEMP_BLOB, True, OCI_DURATION_SESSION);
      CheckOracleError(FPlainDriver, conn.GetErrorHandle,
        Status, lcOther, 'Create Large Object');

      Status := FPlainDriver.LobOpen(conn.GetContextHandle,
        conn.GetErrorHandle, lob, OCI_LOB_READWRITE);
      CheckOracleError(FPlainDriver, conn.GetErrorHandle,
        Status, lcOther, 'Open Large Object');

      Status := FPlainDriver.LobWrite(conn.GetContextHandle,
        conn.GetErrorHandle, lob, buflen, 1,
        buff, buflen, OCI_ONE_PIECE, nil, nil, 0, SQLCS_IMPLICIT);
      CheckOracleError(FPlainDriver, conn.GetErrorHandle,
        Status, lcOther, 'Write Large Object');

      Status := FPlainDriver.LobClose(conn.GetContextHandle,
        conn.GetErrorHandle, lob);
      CheckOracleError(FPlainDriver, conn.GetErrorHandle,
        Status, lcOther, 'Close Large Object');

      Status := FPlainDriver.BindByPos(Handle, BindHandle,
        ErrorHandle, 1, @lob, SizeOf(POCILobLocator),
        SQLT_BLOB, nil, nil, nil, 0, nil,
        OCI_DEFAULT);
      CheckOracleError(FPlainDriver, ErrorHandle, Status, lcExecute, sql);

      ExecuteOracleStatement(FPlainDriver, conn, sql, Handle, ErrorHandle);

      FreeMem(buff);
      FPlainDriver.DescriptorFree(lob, OCI_DTYPE_LOB);
    finally
      FreeOracleStatementHandles(FPlainDriver, Handle, ErrorHandle);
    end;
    conn.Commit;

是否可以使用lob定位器写入长原始数据？如何？

PS。如果表有BLOB字段而不是LONG RAW，则此代码可以正常工作。

Answer 1

自Oracle 8，IIRC以来，LONG RAW已被弃用。使用LONG RAW列没有任何优势，您可以使用TO_LOB函数轻松转换它们（如果可以的话）。通过原始变量或类似的东西加载原始列时，只有2000字节的限制，我不知道LOB定位器是否设计用于RAW类型，我猜他们可以执行一些隐式转换，AFAIK RAW类型在没有LOB接口的情况下使用 - 我不会把事情搞得一团糟。

Answer 2

您应该使用SQLT_LVB类型的数据。

因此：

    ftBlob: begin
      oLength := Length(VData);
      if oLength<2000 then begin
        VDBTYPE := SQLT_BIN;
        oData := pointer(VData);
      end else begin
        VDBTYPE := SQLT_LVB;
        oData := Pointer(PtrInt(VData)-sizeof(Integer));
        Inc(oLength,sizeof(Integer));
      end;
    end;

如何使用OCI和Lob定位器编写LONG RAW数据？

2 个答案: