Relational model stores data in tables (relations): rows = tuples, columns = attributes.
Key components: tables, attributes, tuples, constraints (PK/FK/UNIQUE/NOT NULL).
Mapping ER → relational: entity → table, 1:many → FK on many side, many:many → junction table, multivalued attribute → separate table.
Functional dependency (FD): X → Y means X uniquely determines Y (same X → same Y).
Armstrong axioms: reflexivity (if
Q1 (b) How can you map a conceptual model to a relational model?
Mapping a conceptual (ER) model to a relational model is done by:
Converting entities into tables
Converting attributes into columns
Defining primary keys for each table
Representing relationships using foreign keys
Q1 (c) What is the use of DML in DBMS?
DML (Data Manipulation Language) is used to retrieve and manipulate data in database tables.
Examples: SELECT, INSERT, UPDATE, DELETE.
(d) List two reasons why we may choose to define
Analys av När hundarna kommer av Jessica Schiefauer
I denna text ska jag analysera romanen ”När hundarna kommer” från 2015, skriven av Jessica Schiefauer. Boken handlar om Ester, en tonårstjej som bor i en liten stad, och hennes relationer till andra, bland annat hennes pojkvän Isak, familj och vänner. Parallellt får vi följa Anton, Isaks bror, som utvecklas mycket under berättelsens gång. Romanen tar upp flera viktiga teman, bland annat kärlek och beroende, våld och identitet. Och
Chapter -1
electric field:-the sphere arround a source change in which a test charge would experience a force is called electric field.
Electric field lines: An electric field is represented by same emajinary lines of force which are called electric field.
properties:-1)they are emajinary lines of force.
2)in case of positive source change they are readily directed outward.
3) they are not closed line.
mathematically define of electric field:- the electric force per unit test charge is called
A chemical reaction is a process in which one or more substances, known as reactants, undergo a transformation to form new substances with different chemical properties, known as products. During a chemical reaction, the arrangement of atoms in the reactants changes, leading to the creation of new bonds and the breaking of old ones. Chemical reactions are fundamental to understanding how matter interacts and changes in the world around us.
For example, hydrogen gas combines with
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Important drug terms to know: 1. Onset: Time it takes for the drug to reach the minimum effective concentration 2. Peak drug level: highest drug concentration in the blood 3. Trough drug level: lowest concentration before next dose 4. Duration: Length of time the drug exerts a therapeutic effect 5. Side effects: Secondary drug effects 6. Adverse reactions: Unintentional or unexpected reactions 7. Drug interactions: Changed action of the drug as a result of interaction with another drug 8. Drug |
Research Methods Cheat Sheet
1. Quantitative Research
Purpose: To measure variables, test hypotheses, and generalize findings using numerical data.
Key Features:
Strengths:
Limitations
Mode of Occurrence of Igneous Rocks:- Igneous rocks are formed by the cooling and solidification of molten magma either beneath the Earth’s surface or on it. Their mode of occurrence is closely related to the depth of crystallization, the nature of magma intrusion, and the environment in which the magma solidifies. Broadly, igneous rocks occur in two main modes: intrusive (plutonic) and extrusive (volcanic).
Intrusive (Plutonic) Igneous Rocks:
These rocks form when magma cools slowly beneath the
Activity:-
To observe deflection of a magnetic needle placed near a conductor carrying current.
Apparatus and materials:
Magnetic needle, battery, ammeter, rheost, key, conducting wire etc.
Theory:
When electric current passes through a conductor magnetic field is produced around it.
Procedure:
(1) Magnetic substances are removed from the table and the magnetic needle is placed on it. The cell, rheostat, key and ammeter are connected in series with the experimental wire as shown in Fig. 37. The