Parallelization contract - A parallelization contract, or PACT, is an abstraction from the Stratosphere research project that describes how a data-processing function can be applied...
Parareal - Parareal is a numerical method that parallelizes the solution of time-dependent problems across several time intervals.
Partial Dependency - A partial dependency is a functional dependency in which an attribute depends on a proper subset of a larger determinant, commonly part of a composite...
Partition - In data engineering, a partition is a defined subdivision of a larger dataset or storage structure.
Partitioned global address space - Partitioned global address space, or PGAS, is a parallel programming model that provides a global view of addressable data while retaining a distinction...
Partitioning strategy - A partitioning strategy is the plan for dividing a dataset into manageable parts and maintaining those parts over time.
Percept schema - A percept schema, in AI planning, is a structured description of what an agent can observe and under which conditions that observation becomes available.
Personal cloud - A personal cloud is a collection of remotely accessible storage and related services organized around an individual's information and devices.
Personal knowledge base - A personal knowledge base is an organized collection through which an individual records, connects and retrieves knowledge useful to their work or life.
Physical Independence - Physical independence, usually called physical data independence in databases, is the ability to change physical storage or access arrangements without...
Physical schema - A physical schema describes how a database's data structures are implemented for a particular database system.
Pilot job - A pilot job is a job that acquires computing resources so an application-level system can subsequently schedule tasks within that allocation.
Point-in-time recovery - Point-in-time recovery, or PITR, restores a database to a recoverable state associated with a selected earlier point.
Pointer-based model - A pointer-based model represents relationships through references that lead from one data object or record to another.
Pointer jumping - Pointer jumping is a parallel algorithmic technique that repeatedly replaces a link with a link farther along the same chain, often the current successor's...
Polyglot persistence - Polyglot persistence is the use of different data-storage technologies within an application or organization to suit different data and access needs.
Population protocol - A population protocol is a model of distributed computation in which many simple agents interact in pairs and update their states according to shared rules.
Preferential entailment - Preferential entailment is a way of drawing conclusions by considering the preferred, or most normal, possibilities compatible with the current information.
Prepared statement - A prepared statement is a database statement whose structure is prepared for execution and can be executed with separately supplied parameter values.
Primary key - A primary key is the column or combination of columns chosen to identify each row of a table uniquely.
Prime Attribute - A prime attribute is an attribute that belongs to at least one candidate key of a relation.
Private cloud computing infrastructure - Private cloud computing infrastructure is the computing, storage, networking and management foundation of a cloud provisioned for the exclusive use of one...
Procedural reasoning system - A procedural reasoning system, or PRS, is an AI architecture for selecting and carrying out procedures while responding to a changing environment.
Program dependence graph - A program dependence graph, or PDG, is a directed representation of the data and control dependencies between elements of a program.
Projective Rule - The projective rule, also called the decomposition rule for functional dependencies, states that if X determines a set of attributes Y together with Z, then...
Proof by Contradiction - Proof by contradiction is a reasoning method that establishes a claim by assuming its negation and deriving an impossibility from that assumption and...
Pseudocolumn - A pseudocolumn is a database-provided value that can be referenced in certain SQL contexts much like a column, although it is not an ordinary stored column...
Pseudotransitive Rule - The pseudotransitive rule is an inference rule for functional dependencies: if X determines Y, and Y together with W determines Z, then X together with W...
Quality of Data - Quality of Data, or QoD, here refers to a research approach for expressing required consistency of replicated data through limits on divergence.
Query language - A query language is a language for expressing requests for information from a data system.
Ramification problem - The ramification problem is the problem of representing and reasoning about the indirect effects of actions.
Range query (database) - A range query retrieves database records whose values fall within specified boundaries.
Read - write conflict - A read - write conflict occurs when one transaction reads information that another transaction changes, creating an ordering dependency that matters to...
Recordset - A recordset is a program-accessible collection of records returned or maintained through a data-access interface.
Reduction operator - A reduction operator combines several values into a smaller summary, often one result, by repeatedly applying a combining rule.
Reference metadata - Reference metadata describe the content, methods and quality of statistical data so that users can interpret and assess them.
Referential Constraint - A referential constraint is an integrity rule requiring a reference in one record to correspond to an eligible referenced record.
Reflexive Rule - The reflexive rule for functional dependencies states that an attribute set determines each of its subsets. If Y is a subset of X, then X → Y.
Region connection calculus - Region connection calculus (RCC) is a formal approach to qualitative spatial reasoning that describes relationships between regions, such as separation...
Reification (computer science) - Reification in computer science means making an otherwise implicit, abstract or operational concept into an explicit object or data representation that a...
Relation Instance - A relation instance is the set of tuples belonging to a relation at a particular state or point in the database's evolution.
Relation Profile - A relation profile, in database query optimization, is a statistical description of a relation and its attributes.
Relation Schema - A relation schema specifies the structure of a relation: its name, attributes, and associated domains or types, together with relevant constraints in the...
Relational Data Model - The relational data model represents information through relations: sets of tuples described by named attributes and their domains.
Relational database - A relational database is a database that presents data through tables based on relational concepts, with rows representing records and columns representing...
Relational Model/Tasmania - Relational Model/Tasmania, abbreviated RM/T, is Edgar F. Codd's 1979 proposal for extending the relational model to represent more meaning about data.
Relational Synthesis Algorithm - A relational synthesis algorithm constructs a collection of relation schemas from a specified set of attributes and functional dependencies.