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sdp 6

Beschreibung

Quiz am sdp 6 , erstellt von Жарас Мергазы am 16/12/2017.
Жарас Мергазы
Quiz von Жарас Мергазы, aktualisiert more than 1 year ago
Жарас Мергазы
Erstellt von Жарас Мергазы vor mehr als 6 Jahre
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Zusammenfassung der Ressource

Frage 1

Frage
The PEAR DB functions can be accessed using DB::<function_name>.
Antworten
  • True
  • False

Frage 2

Frage
The string argument of the function for connecting to a database is of the format <DBMS software>://<user account>:<password>@<database server>
Antworten
  • True
  • False

Frage 3

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The PEAR DB functon for connecting to a database is called DB::linkto database('string').
Antworten
  • True
  • False

Frage 4

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• The DBMS software in <DBMS software>://<user account>:<password>@<database server> stands for the particular DBMS software package being connected to: for example mysqli for versions of MySQL starting with version 4.1.2
Antworten
  • True
  • False

Frage 5

Frage
• The PEAR DB function DB::is Error can be used to determine whether any database access operation was successful or not.
Antworten
  • True
  • False

Frage 6

Frage
• In PHP, an _____ array provides pairs of key=>value elements; the value of an element is referenced through its key and all key values in a particular array must be unique.
Antworten
  • Numeric
  • Value
  • String
  • Associative

Frage 7

Frage
• Multi-line PHP comments start with // and end with #.
Antworten
  • True
  • False

Frage 8

Frage
• PHP written in C and usually comes installed with Unix: for other operating systems, the PHP interpreter can be downloaded from http://www.php.net
Antworten
  • True
  • False

Frage 9

Frage
• The PHP start tag is <?php and end the tag is ?>.
Antworten
  • True
  • False

Frage 10

Frage
• Web pages, where part of the information is extracted from databases or other data source, are called dynamic Web pages
Antworten
  • True
  • False

Frage 11

Frage
• In PHP, a ____ array associates a numeric index with each element in the array
Antworten
  • Numeric
  • Associated
  • Variable
  • String

Frage 12

Frage
• PHP variable names start with a $ sign and can include characters, numbers, and the underscore character
Antworten
  • True
  • False

Frage 13

Frage
• Interpolating variables occurs only within single-quoted strings.
Antworten
  • True
  • False

Frage 14

Frage
• PHP programs are executed on the client.
Antworten
  • True
  • False

Frage 15

Frage
• The auto-global predefined PHP variable $_POST is an array that holds all the values entered through form parameters.
Antworten
  • True
  • False

Frage 16

Frage
• JDBC does not distinguish between queries that return single tuples and those that return multiple tuples.
Antworten
  • True
  • False

Frage 17

Frage
• The JDBC _____ libraries are called java.sql.*
Antworten
  • Method
  • Function
  • Class

Frage 18

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• What are the advantages and disadvantages of the embedded SQL approach.
Antworten
  • The main advantage is the query text is part of the source code can be checked for syntax errors and validated against the database schema at compile time. The program is quite readable. Since queries are known in advance, the choice of program variables to hold query results is simple.
  • The main advantage is flexibility in generating queries at runtime. Also, the library of function calls approach is able to call multiple data program.
  • The main disadvantage is the query text is part of the source code can be checked for syntax errors and validated against the database schema at compile time. The program is quite readable. Since queries are known in advance, the choice of program variables to hold query results is simple.
  • Disadvantage are more complex programming, inability to do checking at compile time, and concerns about SQL runtime errors.
  • Disadvantage are the loss of flexibility in changing the query the query at runtime and that all changes to queries must be recompiled.

Frage 19

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• The use of function calls is a more dynamic approach for database programming than embedded SQL.
Antworten
  • True
  • False

Frage 20

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• A _____ object is similar to a cursor in embedded SQL and an iterator in SQLJ.
Antworten
  • Procedure
  • Function call
  • Result Set

Frage 21

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• _____ is the part of the SQL standard that specifies how to write persistent stored modules.
Antworten
  • SQL/PSM
  • XML
  • SQLJ
  • ResultSet

Frage 22

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• Database stored procedures (aka persistent stored modules) are stored and executed by the DBMS at the database server.
Antworten
  • True
  • False

Frage 23

Frage
• Discuss advantages and diadvantages to the library of function calls approach
Antworten
  • Disadvantage are the loss of flexibility in changing the query at runtime and that all changes to queries must be recompiled.
  • The main advantage is flexibility in generating queries at runtime. Also, the library of function calls approach is able to call multiple data program.
  • The main advantage is flexibility in generating queries at compile time. Also, the library of function calls approach is able to call multiple single program.
  • Disadvantages are more complex programming, inability to do checking at compile time, and concerns about SQL runtime errors.
  • The main advantage is the query text is part of source code and can be checked for syntax errors and validated against the data. The program is quite readable.

Frage 24

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• It is necessary to have a binding between the data types of the programming language and the attribute data types in the data model
Antworten
  • True
  • False

Frage 25

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• In SQLJ, embedded SQL commands are preceded by #sql.
Antworten
  • True
  • False

Frage 26

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• One advantage of using an SQLJ translator is that it is not necessary to install drivers such as a JDBC driver.
Antworten
  • True
  • False

Frage 27

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• Describe the three main approaches for database programming.
Antworten
  • • Using a library of database functions. This approach provides what is known as an application programming interface (API) for accessing a database from applications programs.
  • • Using a library of database methods. This approach provides what is known as an application programming interface (API) for accessing a database from applications programs
  • • Embedded SQL. Embeding database commands in a general-purpose programming language. A preprocessor extracts the embedded SQL from the source code and replaces it with function calls to DBMS-generated code.
  • • Embedded SQL. Embeding database commands in a specific-purpose programming language. A preprocessor can not extract code, but function calls to be extracted to DBMS-generated code.
  • • Designing a new database programming language.
  • • Embedded SQL. Embeding database commands in a specific-purpose programming language. A preprocessor extracts the embedded SQL from the source code and replaces it with function calls to DBMS-generating code

Frage 28

Frage
• In XML _____ defines the set of commands (names) that can be used
Antworten
  • • Namespace
  • • Valid
  • • Document
  • • Invalid

Frage 29

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• In XML schema, the tag _____ is used tospecify primary keys.
Antworten
  • • xs:element
  • • xsd:key
  • • psd:schema
  • • xs:sequence

Frage 30

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• A * following an element name means the element can be repeated zero or one times (an optional, single-valued, nonrepeating elements)
Antworten
  • True
  • False

Frage 31

Frage
• If an XML document is well-formed and follows a particular schema, it is _____
Antworten
  • • Namespace
  • • Keys
  • • Invalid
  • • Valid

Frage 32

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• The XML schema, it is possible to specify constraints that correspond to unique and primary key constraints ina relational database, as well as foreign keys constraints
Antworten
  • True
  • False

Frage 33

Frage
• An element that does not have *, +, or ? following the element name means the element must appear exactly once in the document (a required, single-valued, nonrepeating element).
Antworten
  • True
  • False

Frage 34

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• A ? following an element name means that element can be repeated zero or more times in the document (an optional, mult-valued, repeating element).
Antworten
  • True
  • False

Frage 35

Frage
• The basic object in XML is the XML document, which is structured using types and iterators.
Antworten
  • True
  • False

Frage 36

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• How does a well-formed XML document look like?
Antworten
  • • It is syntactically correct: a non-single root element with every element including a matching pair of start/end tags within the start-end of the parent element
  • • It must finish with an XML declaration to indicate the version of XML.
  • • It is syntactically correct: a single root element with every element including a matching pair of start/end tags within the start-end tags of the parent element
  • • It is syntactically correct: a single root element with every element except a matching pair of start/end tags within the start-end tags of the parent elements
  • • It must start with an XML declaration to indicate the version of XML

Frage 37

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• Struct type constructors include the set (T), list (T), bag(T), array(T), and dictionary (K,T) type constructors.
Antworten
  • True
  • False

Frage 38

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• Three major differences between the relational and object database design.
Antworten
  • • In ODB design a binary relationship can be declared in one direction or both. If attributes are included in both directions, there is a potential problem with redundancy.
  • • In ODB design a binary relationship can be declared in one direction or both. If attributes are included in both directions, there is no any problem
  • • In an ODB, operations must be defined early since they are part of the classes specifications. In RDBs, operations may not be defined until implementation
  • • In RDB inheritance is built into the model; ODBs do not have built-in constructs for inheritance.
  • • In an RDB, operations must be defined early since they are part of the class specifications. In an ODB, operations may not be defined until implementation
  • • In ODB inheritance is built into the model; RDBs do not have built-in constructs for inheritance.

Frage 39

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• The typical mechanisms for making an object an object persistent are naming and reachability.
Antworten
  • True
  • False

Frage 40

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• The main property required of an OID is that it be immutable (should not change).
Antworten
  • True
  • False

Frage 41

Frage
• _____ inheritance occurs when a subtype inherits only some of the functions of a supertype.
Antworten
  • • Generalisation
  • • Complete encapsulation
  • • Conditional
  • • Selective

Frage 42

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• In operator overloading (or polymorphism), an operation name may refer to several distinct implementations, depending on the type of object it is applied to.
Antworten
  • True
  • False

Frage 43

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• In ______ all operations that can be applied to an object must be predefined.
Antworten
  • • Half encapsulation
  • • Complete encapsulation
  • • Object identifier
  • • Feedback loop

Frage 44

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• The implementation of an operation is called its signature.
Antworten
  • True
  • False

Frage 45

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• A subtype is used when a new type is needed that is similar but not identical to an already defined type.
Antworten
  • True
  • False

Frage 46

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• The dictionary constructor creates a collection of two tupes (K,V) where the value of a key K can be used to retrieve the can be used to retrieve the corresponding value V.
Antworten
  • True
  • False

Frage 47

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• An ODMS provides a unique identity to each independent object in the database via a unique, system-generated ____.
Antworten
  • • Selective
  • • Complete encaplsulation
  • • Object identifier

Frage 48

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• An object typically has three components: state, timing, and behavior
Antworten
  • True
  • False

Frage 49

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• The 80-20 rule suggests that 80% of the workload is presented by 20% of the most frequently used transactions, which govem the physical database design.
Antworten
  • True
  • False

Frage 50

Frage
• The phases (or activities) of the life cycle are not strictly in sequence; ______ are common among and within the phases of the life cycle.
Antworten
  • • One-shot
  • • Requirements collection
  • • Feedback loop
  • • View integration

Frage 51

Frage
• In the _____ approach to schema design, a scheme is designed for each user group or application based phase, these schemas are merged into a global conecptual schema.
Antworten
  • • Requirements analysis
  • • Feedback loops
  • • Feasibility analysis
  • • One-shot
  • • View integration

Frage 52

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• A large database typically has large transaction volumes and rates, is used in service sector industries, and runs 24/7
Antworten
  • True
  • False

Frage 53

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• Many organizations use data dictionary systems (information repositories) to manage meta-data, i.e., data that describes the database structure, constraints, applications, authorizations, users, and so forth.
Antworten
  • True
  • False

Frage 54

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• What are the three goals of database design?
Antworten
  • a) Satisfy the information content requirements of the generalised users and applications.
  • • Support result
  • • Provide a natural and easy-to-understand structuring of the information.
  • • Support processing requirements and any performance objectives.
  • • Satisfy the information content requirements ofthe specified users and applications.
  • • Provide a comlicated structuring of the information.

Frage 55

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• _______ involves interacting with potential users and user groups to identify their particular problems and needs.
Antworten
  • • view-integration
  • • requirements collection and analysis
  • • feasibility analysis
  • • one-shot
  • • feedback loop

Frage 56

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• A transaction processing system can be characterized as one with several dozen gigabytes of data and a schema with more than 30 or 40 distinct entity types
Antworten
  • True
  • False

Frage 57

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• Identify the three criteria to guide the choice of physical database design options
Antworten
  • • Space utisilation
  • • Availability of vendor services
  • • Transaction throughput
  • • Response time
  • • Familiarity of personnel with the system

Frage 58

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• Identify the three factors to consider in choosing one DBMS over another
Antworten
  • • Space utisilation
  • • Organization-wide adoption of a certain philosophy (data model, vendor, methodology, tools)
  • • Availability of vendor services
  • • Transaction throughput
  • • Response time
  • • Familiarity of personnel with the system

Frage 59

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• _____ is concerned with analyzing potential application areas, identifying the economics of information gathering and dissemination, performing preiliminary cost-benefit studies, determining the complexity of data and processes, and setting up priorities among applications.
Antworten
  • • Feasibility analysis
  • • Requirements collection and analysis
  • • View integration
  • • One-shot
  • • Feedback loops

Frage 60

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• The initial requirements can be expected to be formal, complete, consistent, and correct.
Antworten
  • True
  • False

Frage 61

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• In the ______ schema design approach, the requirements from the different stakeholders are merged into a single set of requirements before the schema design begins.
Antworten
  • • Requirements collection
  • • Feedback loop
  • • Centralized (or one-shot)
  • • Requirements analysis

Frage 62

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• What two things does minimizing redundancy imply?
Antworten
  • • Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.
  • • Reducing the redundant information in tuples.
  • • Making sure the semantics of the attributes is clear in the schema
  • • Minimizing redundant storage of the same information
  • • Disallowing the possibility of generating spurious tuples

Frage 63

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• Third normal form (3NF): R is 2NF and all non-prime attributes are transively dependent on the primary key.
Antworten
  • True
  • False

Frage 64

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• First normal from (1NF): the domain of an attribute must include only atomic (simple, indivisible, scalar) values and the value of any attribute ina tuple must be a single value from the domain of that attribute.
Antworten
  • True
  • False

Frage 65

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A functional dependency is a property of the relation schema R not of a particular legal relation state r or R, therefor it must understands the semantics of the attributes of R.
Antworten
  • True
  • False

Frage 66

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Second normal form (2NF): R is 1NF and every non-prime attribute A in R is fully functionally dependent on the primary key of R
Antworten
  • True
  • False

Frage 67

Frage
What are four informal guidelines that may be used to measure the quality of a relation schema design?
Antworten
  • Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.
  • • Disallowing the possibility of generating spurious tuples.
  • • Reducing the redundant information in tuples
  • • Reducing the NULL values in tuples
  • • Making sure the semantics of the attributes is clear in the schema
  • • Minimizing redundant storage of the same information

Frage 68

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Normalization of data can be considered a process of analyzing the given relation schemas based on their functional dependencies and primary keys to achieve closure on the domain space
Antworten
  • True
  • False

Frage 69

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When mapping a binary M:N relationship type R, create a new relation S to represent R, including as foreign key attributes in S the primary keys of the relations that are the perticipating entity types (their combination in S is the composite primary key of S).
Antworten
  • True
  • False

Frage 70

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The symbol σ (sigma) is used to denote the SELECT operator in the relational algebra
Antworten
  • True
  • False

Frage 71

Frage
A EQUIJOIN uses any of the comparison operators =, <, ≤, >, ≥, or ≠.
Antworten
  • True
  • False

Frage 72

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The symbol π (pi) is used to denote the PROJECT operation in the relational algebra.
Antworten
  • True
  • False

Frage 73

Frage
A THETA JOIN uses the comparison operator =
Antworten
  • True
  • False

Frage 74

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SQL is both a data definition language (DDL) and a data manipulation language (DML).
Antworten
  • True
  • False

Frage 75

Frage
A key uniquely identifies a tuple in a relation
Antworten
  • True
  • False

Frage 76

Frage
When the DELETE operation violates a contraint, the deletion must be rejected.
Antworten
  • True
  • False

Frage 77

Frage
Semantic integrity constarint may be enforced using mechanisms called triggers and assertions.
Antworten
  • True
  • False

Frage 78

Frage
If a multi-table query refers to two or more attributes with the same name, we must qualify the attribute name with the table name, e.g., TABLE.Attribute, to prevent ambiguity.
Antworten
  • True
  • False

Frage 79

Frage
A relation schema may only have one key.
Antworten
  • True
  • False

Frage 80

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Tuples in a relation are ordered.
Antworten
  • True
  • False

Frage 81

Frage
The DELETE operation can violate referential integrity.
Antworten
  • True
  • False

Frage 82

Frage
The INSERT operation can violate domain constraints, key constraints, entity integrity, or referential integrity.
Antworten
  • True
  • False

Frage 83

Frage
The theortical basis of the relation data model is set theory and first-order predicate logic.
Antworten
  • True
  • False

Frage 84

Frage
Attributes that represent the same real-world concept must have identical names in different relations.
Antworten
  • True
  • False

Frage 85

Frage
When the INSERT operation violates a constraint, the default option is to reject the insertion.
Antworten
  • True
  • False

Frage 86

Frage
Attributes must have unique domains.
Antworten
  • True
  • False

Frage 87

Frage
NULL values may mean value unknown, value exits but is not available, attribute does not apply to this tuple (value undefined).
Antworten
  • True
  • False

Frage 88

Frage
All tuples in a relation must be distinct.
Antworten
  • True
  • False

Frage 89

Frage
The $d->query function takes an SQL command as its string argument and sends it to the database server for execution.
Antworten
  • True
  • False

Frage 90

Frage
The _____ is a collection of several libraries of functions for enhancing PHP.
Antworten
  • DBMS
  • PHP Extension and Application Repository (PEAR)
  • MYSQL
  • PHP SQL

Frage 91

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The _____ variable is similar to cursor and iterator variables.
Antworten
  • $d->query
  • post
  • $r

Frage 92

Frage
The abend function can be used to terminate a PHP program if there is an error.
Antworten
  • True
  • False

Frage 93

Frage
The PHP function $d->nextID creates a sequence of unique values for a particular table.
Antworten
  • True
  • False

Frage 94

Frage
Creating a database design that only stores each logical data item in only one place in the database
Antworten
  • Normalization
  • Relational data model
  • Data abstraction
  • Redundancy

Frage 95

Frage
Stores catalog information about schemas and constraints, design decisions, usage standards, application program descriptions, and user information
Antworten
  • Data dictionary (or data repository system or information repository)
  • Relational data model
  • Atomicity property
  • Data abstraction

Frage 96

Frage
Data that is derived from the database files but not explicitly stored
Antworten
  • Relationship
  • Relational data model
  • Virtual data
  • Virtual date

Frage 97

Frage
Represents an association among two or more entities
Antworten
  • . Relationship
  • Relational data model
  • Data abstraction
  • Redundancy

Frage 98

Frage
Represents a database as a collection of tables, where each table can be stored as a separate file
Antworten
  • Data abstraction
  • Atomicity property
  • Redundancy
  • Relational data model

Frage 99

Frage
Ensures that either all the database operations in a transaction are executed or none are
Antworten
  • Atomicity property
  • Atomic property
  • Redundancy
  • Data abstraction

Frage 100

Frage
Storing the same data multiple times
Antworten
  • Redundancy
  • Data abstraction
  • Relationship
  • Virtual data

Frage 101

Frage
Characteristic that allows program-data independence and program-operation independence
Antworten
  • Redundancy
  • Data abstraction
  • Relationship
  • Relational data model

Frage 102

Frage
Choose correct answer
Image:
1 (binary/octet-stream)
Antworten

Frage 103

Frage
Choose correct answer!!
Image:
1 (binary/octet-stream)
Antworten

Frage 104

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Choose one
Image:
12222 (binary/octet-stream)
Antworten

Frage 105

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is typically used to loop over the tuples in a query result
Antworten
  • cursor
  • named
  • positional
  • Impedance mismatch

Frage 106

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iterator is associated with a query result in SQLJ by listing the attribute names and types that appear in the query
Antworten
  • named
  • cursor
  • Impedance mismatch
  • positional

Frage 107

Frage
iterator lists only the attribute types that appear in a query result in SQLJ.
Antworten
  • positional
  • Impedance mismatch
  • named
  • cursor

Frage 108

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is the term used to refer to the problems that occur because of differences between the database model and language model
Antworten
  • Impedance mismatch
  • positional
  • named
  • cursor

Frage 109

Frage
Used to choose a subset of the tuples from a relation that satisfies a selection condition
Antworten
  • • LEFT OUTER JOIN
  • • SELECT
  • • PROJECT
  • • JOIN
  • • INTERSECTION

Frage 110

Frage
Selects certain columns from the table and discards the other columns
Antworten
  • • PROJECT
  • • SELECT
  • • LEFT OUTER JOIN
  • • JOIN
  • • INTERSECTION

Frage 111

Frage
= R S keeps every tuple in the first (left) relation R; if no matching tuples is found in S, then the attributes of S in the join filled with NULL values
Antworten
  • • LEFT OUTER JOIN
  • • SELECT
  • • PROJECT
  • • JOIN
  • • INTERSECTION

Frage 112

Frage
R S in the relational algebra combines related tuples in R and S
Antworten
  • • JOIN
  • • INTERSECTION
  • • LEFT OUTER JOIN
  • • PROJECT
  • • SELECT

Frage 113

Frage
R S in the relational algebra includes all tuples in both R and S
Antworten
  • • JOIN
  • • INTERSECTION
  • • LEFT OUTER JOIN
  • • PROJECT
  • • SELECT
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