The Grid File: An Adaptable, Symmetric Multikey File Structure J. Nievergelt, H. Hinterberger, and K. C. Sevcik present a dynamic, symmetric multikey file structure called the grid file. Traditional file structures for multikey access, such as inverted files, are extensions of single-key structures and have limitations in handling dynamic data. The grid file is designed to adapt to dynamic data, allowing efficient retrieval, range queries, and partially specified queries. It treats all keys symmetrically, avoiding distinctions between primary and secondary keys. The file structure is based on a bitmap approach, treating the search space as a sparse matrix and compressing it for efficient storage and retrieval. The grid file uses a grid partition of the search space and a grid directory to manage data. The grid directory dynamically partitions the space, allowing efficient access to records. The grid file is designed to meet the two-disk-access principle, ensuring that any fully specified query can be retrieved in at most two disk accesses. It also supports efficient range queries and handles dynamic data by splitting and merging grid blocks. The grid file is applicable to various types of queries, including range and partially specified queries. The paper discusses the design of the grid file, its performance, and compares it to other multikey access file structures. The grid file is suitable for applications requiring efficient multikey access, such as information retrieval and geographic data processing. The paper also discusses the implementation of the grid file, including the grid directory, splitting and merging policies, and the dynamic adjustment of the grid partition. Simulation experiments are conducted to evaluate the performance of the grid file, showing its efficiency in handling large volumes of data and its ability to adapt to dynamic environments. The grid file is a promising solution for multikey access in dynamic databases.The Grid File: An Adaptable, Symmetric Multikey File Structure J. Nievergelt, H. Hinterberger, and K. C. Sevcik present a dynamic, symmetric multikey file structure called the grid file. Traditional file structures for multikey access, such as inverted files, are extensions of single-key structures and have limitations in handling dynamic data. The grid file is designed to adapt to dynamic data, allowing efficient retrieval, range queries, and partially specified queries. It treats all keys symmetrically, avoiding distinctions between primary and secondary keys. The file structure is based on a bitmap approach, treating the search space as a sparse matrix and compressing it for efficient storage and retrieval. The grid file uses a grid partition of the search space and a grid directory to manage data. The grid directory dynamically partitions the space, allowing efficient access to records. The grid file is designed to meet the two-disk-access principle, ensuring that any fully specified query can be retrieved in at most two disk accesses. It also supports efficient range queries and handles dynamic data by splitting and merging grid blocks. The grid file is applicable to various types of queries, including range and partially specified queries. The paper discusses the design of the grid file, its performance, and compares it to other multikey access file structures. The grid file is suitable for applications requiring efficient multikey access, such as information retrieval and geographic data processing. The paper also discusses the implementation of the grid file, including the grid directory, splitting and merging policies, and the dynamic adjustment of the grid partition. Simulation experiments are conducted to evaluate the performance of the grid file, showing its efficiency in handling large volumes of data and its ability to adapt to dynamic environments. The grid file is a promising solution for multikey access in dynamic databases.