database simple attritbute
single valued attribute are one character in a record
A simple key consists of a single attribute to uniquely identify an entity occurrence, for example, a student number, which uniquely identifies a particular student. No two students would have the same student number.
Attributes can be classified as identifiers or descriptors. Identifiers, more commonly called keys or key attributes uniquely identify an instance of an entity. If such an attribute doesn't exist naturally, a new attribute is defined for that purpose, for example an ID number or code. A descriptor describes a non-unique characteristic of an entity instance. An entity usually has an attribute whose values are distinct for each individual entity. This attribute uniquely identifies the individual entity. Such an attribute is called a key attribute. For example, in the Employee entity type, EmpNo is the key attribute since no two employees can have same employee number. Similarly, for Product entity type, ProdId is the key attribute. There may be a case when one single attribute is not sufficient to identify entities. Then a combination of attributes can solve this purpose. We can form a group of more than one attribute and use this combination as a key attribute. That is known as a composite key attribute. When identifying attributes of entities, identifying key attribute is very important.
a default value
Dependency means that the one entity dependents on another entity. This is also applicable for the Function also. For Example : If you trying to check the general function which tells you about the rooms availability, which consist of checkFreeRooms() and we can have the checkForACRooms() and CheckForSuits(), So the general function for checking Rooms dependents on the other rooms as above
Complex Attribute: A complex attribute is an attribute that is both composite and multivalued.
Surrogate ID's
Values of columns
Prime attribute are part of any candidate key. Non-prime attribute are not part of any candidate key.
In DBMS a table contains one or more columns there columns are the attribute in DBMS FOR EXAMPLE---say you have a table named "employee information"which have the following columns ID,NAME,ADDRESS THEN id ,name address are the attributes of employee..................
It is the number of attribute of its relation schema. Its is an association among two or more entities..
In database technology, domain refers to the description of an attribute's allowed values. The physical description is a set of values the attribute can have, and the semantic, or logical, description is the meaning of the attribute.
A partial identifier in DBMS is a type of identifier that uniquely identifies a specific entity within a given context or scope. It is a combination of attributes that, when taken together, establish a unique identity for the entity. Partial identifiers may not be unique on their own but become unique when combined with other attributes.
In a database management system (DBMS), an attribute may describe a component of the database, such as a table or a field, or may be used itself as another term for a field. Commonly we can say that an attribute is a "propety" of a database field or its a characteristic or facet of the data field..
A record in a database management system (DBMS) is a basic unit of data storage containing information about a single entity or item. It is composed of fields that represent specific attributes or characteristics of the entity being stored. Records are organized within database tables and can be accessed, updated, or deleted using SQL queries.
the term composite identifier
save point saves the dbms and check point simply check the database thats it simple