Examen Theory BASE DE DATOS

True or False

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

TRUE

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

TRUE

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

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

FALSE

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

FALSE

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

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

TRUE

An index on the primary key is always a primary index

TRUE

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

TRUE

The serial organization does not privilege any search key.

TRUE

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

FALSE

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

FALSE

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

FALSE

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

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

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

FALSE

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

TRUE

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

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

FALSE

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

FALSE

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

FALSE

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

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

FALSE

Consecutive serial organization optimizes space usage.

TRUE

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

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

FALSE

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

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

FALSE

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

FALSE

he bitmap processed with trivalued logic is a multikey index. 

TRUE

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

FALSE

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

TRUE

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

FALSE

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

TRUE

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

TRUE

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

FALSE

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

TRUE

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

FALSE

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

An index on an alternative superkey is a secondary index. 

FALSE

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

TRUE

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

FALSE

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

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

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

FALSE

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

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

TRUE

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

FALSE

A good hash function can improve density

TRUE

Higher BS will result in higher density and more overflow records

FALSE

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

FALSE

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

FALSE

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

TRUE

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

TRUE

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

TRUE

Will auxiliary storage result in decreased efficiency of the location?

TRUE

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

TRUE

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

FALSE

Is input a file consisting of inputs?

FALSE

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

TRUE

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

FALSE

Index requires auxiliary storage

TRUE

Simple dense index cost depending on its structure

TRUE

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

FALSE

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

TRUE

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

TRUE

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

FALSE

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

TRUE

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

FALSE

PL/SQL is an extension of SQL?

TRUE

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

FALSE

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

TRUE

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

FALSE

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

TRUE

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

TRUE

Can the table space be temporary?

TRUE

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

FALSE

Clustered Bitmap Should it be applied on volatile objects?

FALSE

Should a cluster be created before creating the table?

TRUE

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

TRUE

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

TRUE

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

FALSE

Variety is not a feature of big data? 

FALSE

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

TRUE

Classic RDBMS have partition tolerance and availability in CAP theorem

FALSE

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

FALSE

In OLTP sometimes integrity could be lost? 

FALSE

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

TRUE

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

TRUE

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

FALSE

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

FALSE

Granting minimum privileges can be beneficial for preventing sql injection?  

TRUE

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

FALSE

Clustered Bitmap Should be applied on volatile objects? 

FALSE

Tablespace can be temporal ?

TRUE

Inside table space, only one datafiles can be included 

FALSE

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

TRUE

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

TRUE

Index requires Auxiliary Storage 

TRUE

Entry is an archive consisting of entries?

FALSE