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Databases

Store massive amounts of persistent data efficiently

Reliability in Databases

Provide safe access to multiple users

Database Management Systems (DBMSs)

Software systems that store and manage databases

Relational Data Model

Stores data in tables; a database consists of a schema and a database instance

Database Schema

Set of relation schemas {Account, Branch, Customer}

SQL

Language for querying relational data

Hoare State

Variable lookup assigning real numbers to variables in a program and free variables in 𝜙 and 𝜓

Resolution Restriction

Only apply certain resolution steps

Unit Restriction

At least one parent clause has only one literal

Resolution Proof and Unit Restriction

All steps in a resolution proof satisfy the unit restriction

Positive Restriction (P-restriction)

At least one parent clause consists of positive literals

Negative Restriction (N-restriction)

At least one parent clause consists of negative literals

Linear Resolution for a Set of Clauses F

Resolves a sequence of clauses with specific conditions

Resolution-Complete

Any entailment proved by resolution without a restriction is also proved with the resolution

SLD (Selective Linear Definite clause)

Resolution restriction used for logic programs and PROLOG

SLD and Resolution Completeness

Not resolution-complete, but resolution-complete for Horn clauses

Horn Clause

Set of literals with at most one positive literal

SLD and Unit Resolution

Resolution-complete when applied for Horn clauses

SLD

Linear resolution and N-restriction

Fact, Procedure, Goal

Components of a logical problem-solving scenario