| Term | Definition |
|---|
| Field | The Smallest unit of named application data recognized by system software. |
| Data type | A detailed coding scheme recognized by system software, such as a DBMS, for representing organizational data. |
| Physical record | A group of fields stored in adjacent memory locations and retrieved and written. together as a unit by a DBMS. |
| Page | The amount of data read or written by an operating system in one secondary memory (disk) input or output (I/O) operation. For I/O with a magnetic tape, the equivalent term is record block. |
| Blocking Factor | The number of physical records per page. |
| Denormalization | The process of transforming normalized relations into unnormalized physical records specifications |
| Horizontal partitioning | Distributing the rows of a table into several separate files |
| Vertical partitioning | Distributing the columns of a table into several separate physical records |
| Physical file | A named portion of secondary memory (a magnetic tape pr hand disk.) allocated for the purpose of storing physical records |
| Tablespace | A named set of disk storage elements in which physical files for database tables may be stored. |
| Extent | A contiguous section of disk storage space |
| Pointer | A field of data that can be used to locate a related field or record of data. |
| File organization | A technique for physically arranging the records of a file on secondary storage devices. |
| Sequential file organization | The storage of record in a file sequence according to a primary key value. |
| Indexed file organization | The storage of records either sequentially or nonsequentially with an index that allows software to locate individual records |
| Secondary key | One field or a combination of fields for which more then one record may have the same combination of values. Also called a nonunique key. |
| Index | A table or data structure used to determine the location of rows in a file that satisfy some condition. |
| Bitmap index | A table of bits in which each row represents the distinct values of a key and each column is a bit, which when on indicates that the record for that bit column position has the associated field value |
| Join index | An index on columns from two or more tables that come from the same domain of values |
| Hashed file organization | A storage system in which the address for each record is determined using a hashing algorithm. |
| Hashing algorithm | A routine that converts a primary key value into a relative record number ( or relative file address). |
| Hashed index table | A file organization that uses hashing to the map a key into a location in a index, where there is a pointer to the actual data record matching the hashing key. |
| Redundant Array of Inexpensive Disks (RAID) | A set, or array of physical disk drives that appears to the database user (and programs) as if they form one large logical storage unit. |
| Stripe | The set of pages on all disk in a RAID that are the same relative distance from the beginning of the disk drive. |
Combine with other sets
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