1989 – and extends to the current day. The RTM version is 14. Two additional editions provide a superset of features not in the original Express Edition. The sql server 2012 integration services pdf edition is an embedded database engine.
It is limited to 4 GB maximum database size and cannot be run as a Windows service, Compact Edition must be hosted by the application using it. 5 version includes support for ADO. Starting early 2016, Microsoft made this version free of charge to the public. It can also be used as an embedded database. HP base on the Fast Track architecture.
Intended for use as an application component, it did not include GUI management tools. Later, Microsoft also made available a web admin tool. Had workload or connection limits like MSDE, but no database size limit. Initially designed and developed by Sybase Inc. A page is marked with a 96-byte header which stores metadata about the page including the page number, page type, free space on the page and the ID of the object that owns it. Page type defines the data contained in the page: data stored in the database, index, allocation map which holds information about how pages are allocated to tables and indexes, change map which holds information about the changes made to other pages since last backup or logging, or contain large data types such as image or text. A row in a database table cannot span more than one page, so is limited to 8 KB in size.
The data is in the leaf node of the leaves, and other nodes storing the index values for the leaf data reachable from the respective nodes. If the index is non-clustered, the rows are not sorted according to the index keys. A table without a clustered index is stored in an unordered heap structure. However, the table may have non-clustered indices to allow fast retrieval of rows. In some situations the heap structure has performance advantages over the clustered structure. Both heaps and B-trees can span multiple allocation units.