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describe file organisationa file is organized logically as a sequence of records these records are mapped onto disk blocksa fixed-length recordstype
explain mechanism of nested queriessql gives a mechanism for nesting subqueries a subquery is a select from where expression that is nested within
what is data definition language explain it in detailthe sql ddl allows specification of not only a set of relations but also information after each
what is aggregate function briefly describe itaggregate functions are functions that take a collection of values as input and return a one value sql
describe integrity and securitya domain constraintb referential integritya value that appears in one relation
what are data models explain it detailentity relationship model rectanglesellipsediamondslinesrelational model relational model use a collection of
describe relational modelstructure of relational data basebasic structuredatabase schemakeysschema diagramquery
explain about database system structurestorage manager authorization and integrity managertransaction managerfile managerbuffer managerstorage
define decision tree classifiersas the name suggests decision tree classifiers use a tree every leaf node has an associated class and every internal
what are the various forms of data transparencya fragmentation transparencyb replication transparencyc location transparency
what is vertical fragmentationvertical fragmentation divides the relation by decomposing the scheme r of relation
what is horizontal fragmentationhorizontal fragmentation divides the relation by assuming every tuple of r to one or more
what are the two approaches to store relations in distributed databasea replicationb
what is a heterogeneous distributed databasein a heterogeneous distributed database dissimilar sites may use different schemas and dissimilar dbms sw
what is a homogeneous distributed databasein homogeneous distributed databases all sites have the same database management system software are aware
write a query to define tables students and teachers as sub tables of peoplecreate table students of student under peoplecreate table teachers of
how to create values of structured typeconstructor functions are used to make values of structured types a function with the similar name as a
list some instances of collection typesa setsb arraysc
what is nested relational modelthe nested relational model is an extension of relational model in which domains might be either atomic or relation
how persistent programming languages differ from traditional programming languagesdatabase languages vary from traditional programming languages in
define object-relational systems systems that give object-oriented extensions to relational systems are known as object-relational
why containment is important in oosystemscontainment is an significant concept in oosystems because it allows dissimilar users to view data at
what is object containmentreferences among objects can be used to model dissimilar real-world
what are composite objectsobjects that have other objects are known as complex objects or composite
what is meant by object identifiersobject-oriented systems use an object identifier to recognize objects object identifiers are unique that is every