RAID 4 multiple records are stored in a stripe but error correction on one disk. RAID 5 each drive contains data and parity pages. Database Architectures Hierarchical Model - takes the shape of a tree. A parent may own an arbitrary number of children, but each child may have only a single parent. N relationships are represented by multiple hierarchical structures, which unfortunately increase redundancy.
Network databases are an extension of the hierarchical model that uses pointers for efficiency.
Relational model Object-oriented database attributes and operations are stored together. Offers wide range of data types. Multidimensional databases used for data warehouse applications, using a multidimensional table or a star schema.