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A dense index in databases is a file with pairs of keys and pointers for every record in the data file. Every key in this file is associated with a particular pointer to a record in the sorted data file. In clustered indices with duplicate keys, the dense index points to the first record with that key. [3]
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Source deduplication ensures that data on the data source is deduplicated. This generally takes place directly within a file system. The file system will periodically scan new files creating hashes and compare them to hashes of existing files. When files with same hashes are found then the file copy is removed and the new file points to the old ...
The files have names that begin with the table name and have an extension to indicate the file type. MySQL uses a .frm file to store the definition of the table, but this file is not a part of the MyISAM engine; instead it is a part of the server. The data file has a .MYD (MYData) extension. The index file has a .MYI (MYIndex) extension.
The join operation defined for relational databases is often referred to as a natural join (⋈). In this type of join, two relations are connected by their common attributes. MySQL's approximation of a natural join is the Inner join operator. In SQL, an INNER JOIN prevents a cartesian product from occurring when there are two tables in a query.
ACFS [2] is a standard-based POSIX (Linux, UNIX) and Windows cluster file system with full cluster-wide file and memory mapped I/O cache coherency and file locking. ACFS provides direct I/O for Oracle database I/O workloads. ACFS implements indirect I/O however for general purpose files that typically perform small I/O for better response time.
Oracle Corporation: 2005 Linux: NILFS: NTT: 2005 Linux: VMFS3: VMware: ... Maximum file size Maximum volume size [cd] Max number of files See also. List of file systems;
In early May 2019, an update was deployed to Stack Overflow's development version. It contained a bug which allowed an attacker to grant themselves privileges in accessing the production version of the site.