ch2-DB

describe the DETAILS of data+ low level :

common for web applications.

DML can be embedded in a general-pupose programming language such as java, C++ :

the higher-level schemas themselves are_________

in three-tier archeticture, the client is connected directly to the DB

PROGRAMS refer to_________, and are mapped by the DBMS to the________ for EXCUTION.

why called two-tier ?

how the client connect to the server?

example of user defined operations:

in centralized architecture clients can access the specialized servers as needed:

distributed database systems have now come to be known as client-server based DBS.

when a schema at a lower level is changed, ONLY the ______ between this schema and higher-level shemas need to be change

constrains must be enforced at particular time :

combine everything into single system and all processing is done at centerlized site:

constructs are used to define the data base structure:

used to specify the conceptual schema and to define the internal and external schemas:

internal schem uses implementation data model

provide concepts that fall between phasical and conceptual:

conceptual schema uses conceptual or implementation data model

the main feature of three-tier is security

a component of the schema or an object within the schema:

which of the data models is closer to the users+ High level :

refer to the database when it is initially loaded to the system:

DDL and DML are two types of DBMS langugeas:

external schema: describe the various USER VIEWS .

used to specify the retrivlas and updates of DB:

self-describing data model: combine the data description and the data values .

example: relational data models used in many Commercial systems:

an illustrative dispaly for most aspect of the Database:

costructs typically include: