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Examples of such operations are requesting a read operation, reading, writing, aborting, committing, requesting a lock, locking, etc. Often, only a subset of the transaction operation types are included in a schedule. Schedules are fundamental concepts in database concurrency control theory. In practice, most general purpose database systems ...
The problem of deciding whether for a given Datalog program there is an equivalent nonrecursive program (corresponding to a positive relational algebra query, or, equivalently, a formula of positive existential first-order logic, or, as a special case, a conjunctive query) is known as the Datalog boundedness problem and is undecidable.
The term closure is often used as a synonym for anonymous function, though strictly, an anonymous function is a function literal without a name, while a closure is an instance of a function, a value, whose non-local variables have been bound either to values or to storage locations (depending on the language; see the lexical environment section below).
Derby (aka Java DB) Apache License 2.0 Empress Embedded Database: Proprietary EnterpriseDB: Proprietary eXtremeDB: Proprietary Exasol: Proprietary Extensible Storage Engine: Proprietary FileMaker Pro: Proprietary Firebird: MPL/GPL/LGPL FoundationDB: Apache License 2.0 FrontBase: Proprietary Greenplum: Apache License 2.0 H2: MPL/GPL/LGPL Helix ...
A pool of database connections can be created and then shared among the applications that need to access the database. The connection object obtained from the connection pool is often a wrapper around the actual database connection. The wrapper understands its relationship with the pool, and hides the details of the pool from the application.
An object–relational database (ORD), or object–relational database management system (ORDBMS), is a database management system (DBMS) similar to a relational database, but with an object-oriented database model: objects, classes and inheritance are directly supported in database schemas and in the query language.
Hibernate ORM (or simply Hibernate) is an object–relational mapping [2]: §1.2.2, [12] tool for the Java programming language. It provides a framework for mapping an object-oriented domain model to a relational database.
In database design, object-oriented programming and design, has-a (has_a or has a) is a composition relationship where one object (often called the constituted object, or part/constituent/member object) "belongs to" (is part or member of) another object (called the composite type), and behaves according to the rules of ownership.