Portable Executable

Introduction

Portable Executable is a file format for executables in Windows Operating Systems. It would encapsulates the required information for the Windows OS loaders.

Dynamic-link Library (DLL)

It is Microsoft’s implementation of the shared library. The file format of DLL is the same as the Window EXE files.

Command Prompt (cmd.exe)

Introduction

Command Prompt is command-line interpreter on Windows Platforms.

 

Logical Commands

for 

for loop to parse file or output of a command

 

 

Common Commands

call

Starts a batch file from another batch file and returns when one ends

cd

change current working directory

copy

copy files from one location to another

date

display system date

dir

display contents of a directory

echo

print test to display

 

Excel VBA – Oracle Database Connection with ADO

ActiveX Data Object (ADO)

ADO is Microsoft’s Component Object Model (COM) objects for accessing data source.

ADO Object Model

IC46663

Example

Source Code

Sub main()
 Dim objConnection As New ADODB.Connection
 Dim Recordset As New ADODB.Recordset
 
 strcon = "Provider=MSDAORA;Data Source=<IP>:<PORT>/<SID>;User Id=<USER NAME>;Password=<PASSWOR>;"
 objConnection.ConnectionTimeout = 0
 objConnection.Open (strcon)
 
 
 objConnection.CommandTimeout = 15
 
 
 sqlStr = "select * from USER_TABLES"
 
 Dim cmd1 As New ADODB.Command
 cmd1.ActiveConnection = objConnection
 cmd1.CommandText = sqlStr
 Set Recordset = cmd1.Execute

 
 objConnection.Close
 
End Sub

 

Points to Note

  • OLE DB is a way to access data store while ADO is a way to access data.

Reference:

https://support.microsoft.com/en-us/kb/194973

 

 

 

 

 

OLE DB, ADO, ODBC

Object Linked and Embedding, Database (OLE DB)

It is an API for access various datasource in a uniform manner.

ole db

ActiveX Data Object (ADO)

It is a middleware layer for accessing and manipulate data through OLE DB Provider.

ADO

Reference:

https://msdn.microsoft.com/en-us/library/ms675532(v=vs.85).aspx

https://en.wikipedia.org/wiki/ActiveX_Data_Objects

Open Database Connectivity (ODBC)

It is a api for accessing relational database management system (RDBMS).

The task is accomplished by ODBC Driver.

odbc