Examen Theory BASE DE DATOS

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While B tree structure is suitable for identifying indexing keys, for non-identifying indexing keys the B+ tree structure is preferable.

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1

While B tree structure is suitable for identifying indexing keys, for non-identifying indexing keys the B+ tree structure is preferable.

TRUE

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2

In a direct addressing organization, the privileged key is always an identifier.

TRUE

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3

Distributed free space technique enables the update operation with fewer accesses in non-consecutive sequential organizations (as long as the sorting key is not modified).

TRUE

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4

The bi-directional B+ tree can rotate both to the left node and to the right node.

FALSE

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5

In a direct addressing organization, there are no collisions or overflows.

FALSE

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6

The addressing space N must always be less than or equal to the cardinality of the domain on which the hashing key is defined. TRUE

TRUE

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7

Saturation overflow management policies in hashed organizations increase the density of the data area.

TRUE

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8

An index on the primary key is always a primary index

TRUE

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9

The ideal density measures the goodness of the physical-logical design.

TRUE

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10

The serial organization does not privilege any search key.

TRUE

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11

In ORACLE, every tablespace is associated with a data file (datafile), and any data file can contain objects from different tablespaces

FALSE

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12

In a non-identifying selection on serial organization, the greater  the number of search keys involved, the greater the cost of the process.

FALSE

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13

A simple hashed organization has as many privileged search keys as attributes included in the Hashing Key.

FALSE

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14

The search in a  multi-key hashed organization can only be carried out if it has been provided a value for each of the keys involved in the hashing.

FALSE

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15

Although one session is keeping an RS lock on some rows of a table, another session can acquire an RX lock on the rest of the rows of that table and then delete some of them.

TRUE

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16

All transactional databases must meet the ACID characteristics: availability, clarity, integrity and durability.

FALSE

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17

B-tree is an ordered, balanced index which density can drop to 50%.

TRUE

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18

Oracle's "hints" report on physical structures recommended by the DBMS to improve efficiency, so that the user can implement an improved physical design.

FALSE

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19

SQL injection is a technique to protect the confidentiality of the database.

FALSE

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20

Simple hashed organization has as many privileged keys as attributes included in the Hashing Key

FALSE

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21

Overflow management with “bucket chaining” (extension) is a saturation type policy.

FALSE

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22

Although one session is keeping an RS look on same of rows of a table, another session can acquire an RX lock of the rest of the rows of that table and then delete some of them.

TRUE

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23

An expanded record is the one growing (in size) when an update is applied to it.

FALSE

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24

Consecutive serial organization optimizes space usage.

TRUE

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25

The selection of records through non-privileged search keys in any base organization (send, sequential, hashed) involves performing a full scan on the file.

TRUE

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26

In a non-consecutive organization, smaller bucket space produces higher density

FALSE

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27

Initially (before opening the file) the real density of a consecutive serial file is equal to the density of the same file with a consecutive sequential organization.

TRUE

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28

In oracle, the parameters of PCTFREE and PCTUSED are complementary (add up to 100%).

FALSE

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29

In a sequential organization, the sorting key should be an identifier (unless it compromises several fields).

FALSE

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30

he bitmap processed with trivalued logic is a multikey index.

TRUE

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31

A distributed database must always meet the three features defined by the CAP triangle (Consistency, Availability and Partition tolerance).

FALSE

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32

In a direct addressing organization, the privilege key is always an identifier.

TRUE

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33

In ORACLE, every tablespace is associated with a datafile and any datafile can contain objects from different tablespaces.

FALSE

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34

n a cluster, every insertion operation involves a location operation.

TRUE

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35

The ideal density (of a record) is always greater than or equal to the real density.

TRUE

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36

Overflow management with “bucket chaining” (extensions) is a saturation type policy).

FALSE

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37

In a non-consecutive sequential file, the virtual directory supports inserting empty buckets anywhere in the file.

TRUE

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38

In a direct addressing organization, there are no collisions or overflows.

FALSE

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39

The difference between B tree and B* tree is structural (node design), and so B* tree has a higher order (for the same file and indexation key)

FALSE

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40

An index on an alternative superkey is a secondary index.

FALSE

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41

The concept of 'bucket extent' in non-consecutive organizations is analogous to the concept of 'blocking factor' in consecutive organizations.

TRUE

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42

The 'cell partitioning' is part of the binary search algorithm, which divides the search space in half on each access.

FALSE

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43

Searching using secondary indexes can return a multiple result (several addresses), and if they were too many addresses, it could be less efficient than a full scan.

TRUE

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44

The selection of records through non-privileged search keys in any base organization (serial, sequential, hashed) involves performing a FULL SCAN of the file.

TRUE

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45

Overflow management with “bucket chaining” (extensions) is a saturation type policy.

FALSE

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46

Initially (before operating the file) the real density of a consecutive serial file is equal to the density of the same file with consecutive sequential organization.

TRUE

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47

A 'partial index' only indexes some privileged records, and therefore searches using it can fail, requiring a secondary retrieval mechanism.

TRUE

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48

In Relative Direct Addressing, the hash key is the bucket address

FALSE

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49

A good hash function can improve density

TRUE

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50

Higher BS will result in higher density and more overflow records

FALSE

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51

Values that produce the same address for a given hash are called homonymous keys

FALSE

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52

For the update, if the new record doesn't fit, will it be located and rewritten?

FALSE

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53

We have a parent overflow policy that is based on the zone in which the overflow record will be stored

TRUE

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54

If the overflow register does not conform to the new computed address, it will be called bounce

TRUE

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55

Through chained saturation, individual (flyover) records are pointed (record chaining), therefore requiring relative double-precision pointers

TRUE

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56

Will auxiliary storage result in decreased efficiency of the location?

TRUE

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57

In record chaining, the records in the overflow area are stored serially

TRUE

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58

The symbolic identifier pointer, which is a logical identification of a record, is used to identify physical records

FALSE

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59

Is input a file consisting of inputs?

FALSE

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60

INDEX is a file consisting of entries and its entries are related to a single record

TRUE

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61

Is one of the disadvantages of indices that the hit ratio will increase using the index?

FALSE

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62

Index requires auxiliary storage

TRUE

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63

Simple dense index cost depending on its structure

TRUE

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64

Depending on the coverage of the index, they could be primary and Partial index

FALSE

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65

Binary tree on secondary storage, showing neighborhood and balance problems?

TRUE

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66

Does the relational DBMS use logical (symbolic) pointers and is it a truly accessible technology?

TRUE

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67

Relational DBMS developed in the late 60's, and used during the 70's?

FALSE

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68

Oracle V1-V2 as the first "commercial" RDBMS was born during 1978-79 ?

TRUE

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69

DBMS is a collection of information that is organized so that it can be easily accessed, managed and updated?

FALSE

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70

PL/SQL is an extension of SQL?

TRUE

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71

In 1983 the client-server architecture and the distributed database were introduced in oracle?

FALSE

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72

Does each data file have a segment and each segment consists of several extensions?

TRUE

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73

Within the table space, only one data file can be included

FALSE

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74

DB-block can take one of five sizes: 4 KB, 8 KB, 16 KB, 32 KB and 64 KB ?

TRUE

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75

Isn't it necessary for a DBA to master database technologies?

TRUE

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76

Can the table space be temporary?

TRUE

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77

Is the index selection problem (ISP) part of the logical design?

FALSE

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78

Clustered Bitmap Should it be applied on volatile objects?

FALSE

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79

Should a cluster be created before creating the table?

TRUE

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80

One of the advantages of clustering is that access to the combined rows is much more efficient?

TRUE

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81

Can the cluster be indexed or hashed and the logs kept sorted in their bucket?

TRUE

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82

Do HINTS allow the DBMS to automatically choose when planning how to solve the sentence?

FALSE

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83

Variety is not a feature of big data?

FALSE

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84

Big data is a set of techniques and technologies required to process high volumes of data?

TRUE

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85

Classic RDBMS have partition tolerance and availability in CAP theorem

FALSE

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86

Real-Time Analytic Processing is good for long term decisions?

FALSE

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87

In OLTP sometimes integrity could be lost?

FALSE

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88

The cluster can be indexed, or hashed , and records can be kept sorted in their bucket?

TRUE

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89

One of the advantages of clusters is that access to combined rows is much more efficient?

TRUE

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90

The cluster ensures that none of the joint rows for any given value of the cluster is physically stored within

FALSE

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91

If we are using connection string, it is better not to use try {…} catch {…} structure?

FALSE

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92

Granting minimum privileges can be beneficial for preventing sql injection?

TRUE

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93

Creating views for running queries, and to_do tables for batching writes can not help preventing sql injection

FALSE

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94

Clustered Bitmap Should be applied on volatile objects?

FALSE

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95

Tablespace can be temporal ?

TRUE

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96

Inside table space, only one datafiles can be included

FALSE

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97

Each data file has a segment and each segment consist of several extensions?

TRUE

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98

Binary tree on secondary storage, shows vicinity and balancing problems?

TRUE

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99

Index requires Auxiliary Storage

TRUE

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100

Entry is an archive consisting of entries?

FALSE

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