Sequences are the simplest way to represent a macromolecule. The structure of genes that code for the sequence of amino acids in proteins is produced in this form by genome sequencing projects. A simple database might be a single file containing many records, each of which includes the same set of information. Many laboratories generate large volumes of such data as DNA sequences, gene expression information, three-dimensional molecular structure and high-throughput screening. Consequently, they must develop effective databases for storing and quickly accessing data. For each type of data, it is likely that a different database organization must be used. A database must be designed to allow efficient storage, search and analysis of the data it contains. Designing a high-quality database is complicated by the fact that there are several formats for many types of data and a wide variety of ways in which scientists may want to use the data. Many of these databases are best built using a relational database architecture, often based on Oracle. A strong background in relational databases is a fundamental requirement for working in database development. Having some background in the molecular biology techniques used to generate the data is also important. Most critical for the bioinformatics specialist is to have a strong working relationship with the researchers who will be using the database and the ability to understand & interpret their needs into functional database capabilities.