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what is the difference between OLE DB and ODBC data sources?

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What is Ole OLE DB and ODBC?

OLE DB and ODBC are APIs that provide access to a range of data sources. Microsoft designed ODBC to access SQL data and OLE DB to access any type of data in a COM environment. Many people don't entirely understand the factors that led Microsoft to implement OLE DB.

Does OLE DB use ODBC?

First of all, it is good to know that ADO.NET used OLE DB providers to access data while OLE DB uses ODBC to access relational databases.

Is OLE DB faster than ODBC?

2- OLE DB is more faster than ODBC ... Microsoft ADO, OL DB, and ODBC MDAC Components. Developers can use any of MDAC's components (ODBC, OLE DB, and ADO) to connect to several relational and non-relational data stores.

What is OLE DB data source?

Object Linking and Embedding Database (OLE DB) is a connectivity method similar to Open Database Connectivity (ODBC) and uses the same core application programming interface (API) to help bridge communication between client applications and a variety of data sources.


According to ADO: ActiveX Data Objects, a book by Jason T. Roff, published by O'Reilly Media in 2001 (excellent diagram here), he says precisely what MOZILLA said.

(directly from page 7 of that book)

  • ODBC provides access only to relational databases
  • OLE DB provides the following features
    • Access to data regardless of its format or location
  • Full access to ODBC data sources and ODBC drivers

So it would seem that OLE DB interacts with SQL-based datasources THRU the ODBC driver layer.

alt text

I'm not 100% sure this image is correct. The two connections I'm not certain about are ADO.NET thru ADO C-api, and OLE DB thru ODBC to SQL-based data source (because in this diagram the author doesn't put OLE DB's access thru ODBC, which I believe is a mistake).


ODBC:- Only for relational databases (Sql Server, Oracle etc)

OLE DB:- For both relational and non-relational databases. (Oracle, Sql-Server, Excel, raw files, etc)


Here's my understanding (non-authoritative):

ODBC is a technology-agnostic open standard supported by most software vendors. OLEDB is a technology-specific Microsoft's API from the COM-era (COM was a component and interoperability technology before .NET)

At some point various datasouce vendors (e.g. Oracle etc.), willing to be compatible with Microsoft data consumers, developed OLEDB providers for their products, but for the most part OLEDB remains a Microsoft-only standard. Now, most Microsoft data sources allow both ODBC and OLEDB access, mainly for compatibility with legacy ODBC data consumers. Also, there exists OLEDB provider (wrapper) for ODBC which allows one to use OLEDB to access ODBC data sources if one so wishes.

In terms of the features OLEDB is substantially richer than ODBC but suffers from one-ring-to-rule-them-all syndrome (overly generic, overcomplicated, non-opinionated).

In non-Microsoft world ODBC-based data providers and clients are widely used and not going anywhere.

Inside Microsoft bubble OLEDB is being phased out in favor of native .NET APIs build on top of whatever the native transport layer for that data source is (e.g. TDS for MS SQL Server).


ODBC and OLE DB are two competing data access technologies. Specifically regarding SQL Server, Microsoft has promoted both of them as their Preferred Future Direction - though at different times.

ODBC

ODBC is an industry-wide standard interface for accessing table-like data. It was primarily developed for databases and presents data in collections of records, each of which is grouped into a collection of fields. Each field has its own data type suitable to the type of data it contains. Each database vendor (Microsoft, Oracle, Postgres, …) supplies an ODBC driver for their database.

There are also ODBC drivers for objects which, though they are not database tables, are sufficiently similar that accessing data in the same way is useful. Examples are spreadsheets, CSV files and columnar reports.

OLE DB

OLE DB is a Microsoft technology for access to data. Unlike ODBC it encompasses both table-like and non-table-like data such as email messages, web pages, Word documents and file directories. However, it is procedure-oriented rather than object-oriented and is regarded as a rather difficult interface with which to develop access to data sources. To overcome this, ADO was designed to be an object-oriented layer on top of OLE DB and to provide a simpler and higher-level – though still very powerful – way of working with it. ADO’s great advantage it that you can use it to manipulate properties which are specific to a given type of data source, just as easily as you can use it to access those properties which apply to all data source types. You are not restricted to some unsatisfactory lowest common denominator.

While all databases have ODBC drivers, they don’t all have OLE DB drivers. There is however an interface available between OLE and ODBC which can be used if you want to access them in OLE DB-like fashion. This interface is called MSDASQL (Microsoft OLE DB provider for ODBC).

SQL Server Data Access Technologies

Since SQL Server is (1) made by Microsoft, and (2) the Microsoft database platform, both ODBC and OLE DB are a natural fit for it.

ODBC

Since all other database platforms had ODBC interfaces, Microsoft obviously had to provide one for SQL Server. In addition to this, DAO, the original default technology in Microsoft Access, uses ODBC as the standard way of talking to all external data sources. This made an ODBC interface a sine qua non. The version 6 ODBC driver for SQL Server, released with SQL Server 2000, is still around. Updated versions have been released to handle the new data types, connection technologies, encryption, HA/DR etc. that have appeared with subsequent releases. As of 09/07/2018 the most recent release is v13.1 “ODBC Driver for SQL Server”, released on 23/03/2018.

OLE DB

This is Microsoft’s own technology, which they were promoting strongly from about 2002 – 2005, along with its accompanying ADO layer. They were evidently hoping that it would become the data access technology of choice. (They even made ADO the default method for accessing data in Access 2002/2003.) However, it eventually became apparent that this was not going to happen for a number of reasons, such as:

  1. The world was not going to convert to Microsoft technologies and away from ODBC;
  2. DAO/ODBC was faster than ADO/OLE DB and was also thoroughly integrated into MS Access, so wasn’t going to die a natural death;
  3. New technologies that were being developed by Microsoft, specifically ADO.NET, could also talk directly to ODBC. ADO.NET could talk directly to OLE DB as well (thus leaving ADO in a backwater), but it was not (unlike ADO) solely dependent on it.

For these reasons and others, Microsoft actually deprecated OLE DB as a data access technology for SQL Server releases after v11 (SQL Server 2012). For a couple of years before this point, they had been producing and updating the SQL Server Native Client, which supported both ODBC and OLE DB technologies. In late 2012 however, they announced that they would be aligning with ODBC for native relational data access in SQL Server, and encouraged everybody else to do the same. They further stated that SQL Server releases after v11/SQL Server 2012 would actively not support OLE DB!

This announcement provoked a storm of protest. People were at a loss to understand why MS was suddenly deprecating a technology that they had spent years getting them to commit to. In addition, SSAS/SSRS and SSIS, which were MS-written applications intimately linked to SQL Server, were wholly or partly dependent on OLE DB. Yet another complaint was that OLE DB had certain desirable features which it seemed impossible to port back to ODBC – after all, OLE DB had many good points.

In October 2017, Microsoft relented and officially un-deprecated OLE DB. They announced the imminent arrival of a new driver (MSOLEDBSQL) which would have the existing feature set of the Native Client 11 and would also introduce multi-subnet failover and TLS 1.2 support. The driver was released in March 2018.


• August, 2011: Microsoft deprecates OLE DB (Microsoft is Aligning with ODBC for Native Relational Data Access)

• October, 2017: Microsoft undeprecates OLE DB (Announcing the new release of OLE DB Driver for SQL Server)


On a very basic level those are just different APIs for the different data sources (i.e. databases). OLE DB is newer and arguably better.

You can read more on both in Wikipedia:

  1. OLE DB
  2. ODBC

I.e. you could connect to the same database using an ODBC driver or OLE DB driver. The difference in the database behaviour in those cases is what your book refers to.


Both are data providers (API that your code will use to talk to a data source). Oledb which was introduced in 1998 was meant to be a replacement for ODBC (introduced in 1992)