Examen Theory BASE DE DATOS

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

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

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).

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

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

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

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

An index on the primary key is always a primary index

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

The serial organization does not privilege any search key.

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

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

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

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.

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.

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

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

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

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

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

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

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.

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

Consecutive serial organization optimizes space usage.

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

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

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.

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

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

he bitmap processed with trivalued logic is a multikey index.

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

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

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

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

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

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

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

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

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)

An index on an alternative superkey is a secondary index.

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

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

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.

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

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

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.

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

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

A good hash function can improve density

Higher BS will result in higher density and more overflow records

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

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

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

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

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

Will auxiliary storage result in decreased efficiency of the location?

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

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

Is input a file consisting of inputs?

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

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

Index requires auxiliary storage

Simple dense index cost depending on its structure

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

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

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

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

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

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

PL/SQL is an extension of SQL?

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

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

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

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

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

Can the table space be temporary?

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

Clustered Bitmap Should it be applied on volatile objects?

Should a cluster be created before creating the table?

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

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

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

Variety is not a feature of big data?

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

Classic RDBMS have partition tolerance and availability in CAP theorem

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

In OLTP sometimes integrity could be lost?

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

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

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

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

Granting minimum privileges can be beneficial for preventing sql injection?

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

Clustered Bitmap Should be applied on volatile objects?

Tablespace can be temporal ?

Inside table space, only one datafiles can be included

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

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

Index requires Auxiliary Storage

Entry is an archive consisting of entries?