All the information stored in a database file is organized into 2 KB pages. There are a variety of page types used to store data.
The first page in every database is the database header page. It stores 256 commit bytes that track user operations in a multiuser environment. There is no set order for subsequent pages.
These pages store indexes. Microsoft Jet 3.0 and 3.5 use an entirely new layout format for compressing index data that results in a substantial reduction in storage size and a significant reduction in the time needed to create indexes that are highly duplicated. When the database is compacted, Microsoft Jet 3.0 and 3.5 rewrite a table’s records in primary key order.
LV pages store two types of data. The first is Memo data that has flowed over from data pages. The second type includes all other binary data types, such as Long Binary (OLE Object) fields. In Microsoft Jet 2.0, these pages are all stored in one hidden table. This results in contention issues when multiple users are accessing Microsoft Jet. In Microsoft Jet 3.0 and 3.5, long values of a particular field are stored with other long values of the same field. This helps reduce multiuser contention when using long values from different fields. Additionally, LV pages now have two distinct types: Fixed-length LV pages are used internally for special database scenarios; variable-length LV pages are used for external data.
These pages contain the system tables MSysACES, MSysObjects, MSysQueries, and MSysRelationships. These system tables are discussed in the following section.
See Also For more information on pages, see Chapter 6, “Creating Multiuser Applications,” and Chapter 13, “Optimizing Performance.”