Developed by Google, BigTable is a database application that has a more complex structure and interface than many NoSQL datastores, with a hierarchy and multidimensional access. It is designed to handle very large data loads by running on big clusters of commodity hardware. It has per-row transaction guarantees, but it doesn't offer any way to atomically alter larger numbers of rows. It uses the Google File System as its underlying storage, which keeps redundant copies of all the persistent files so that failures can be recovered from.

Each table within the database is split into multiple rows, with each row addressed with a unique key string. The values inside the row are arranged into cells, with each cell identified by a column family identifier, a column name, and a timestamp.

The row keys are stored in ascending order within file chunks called shards to ensure efficient operations of accessing continuous ranges of keys.

The column family can be viewed as a type or a class in a programming language, each representing a set of data values that share some common properties. Only a small number of these families are expected per table, and they should be altered infrequently, so in practice they're often chosen when the table is created. They can have properties, constraints, and behaviors associated with them.

Column names are quite different from column names in a relational database. They are defined dynamically, rather than specified ahead of time, and they often hold actual data themselves. The timestamp allows a given cell to have multiple versions over time, as well as making it possible to expire or garbage collect old data.

A given piece of data can be uniquely addressed by looking in a table for the full identifier that conceptually looks like row key, then column family, then column name, and finally timestamp. All the values for a given row key in a particular column family can be read easily so they can compared to a column in a relational database.