MC Which statement is NOT CORRECT? Table cardinality is another way of referring to the number of columns in a table. correct An index can be used to create a physical ordering of rows. incorrect A DAS does not offer out-of-the-box capabilities for centralized storage management and sharing unused disk capacity across servers. incorrect The management of data storage is more expensive than the purchase of storage hardware, which is why businesses opt for enterprise storage subsystems. incorrect MC Which statement is NOT CORRECT? To store the same amount of data, RAID 1 needs twice the amount of storage capacity compared to RAID 0. incorrect RAID level 0 is used if performance is more important than fault tolerance. incorrect RAID level 5 strikes a balance between read and write performance, storage efficiency, and fault tolerance. incorrect Block level striping as used in RAID 0 does not increase read performance. correct MC Statement 1: When opting for hard drive back-ups to maintain data availability in case of a calamity, the RPO depends on the underlying infrastructure. Choosing a SAN as storage subsystem might be a solution here, as it keeps the burden of data and backup related traffic from the LAN and from the servers.

Statement 2: Log shipping is a technique which is used for preserving the transaction context of a DBMS in case of a calamity. The remote DBMS used for replication can use the primary log for restoring transactions that were ongoing at the primary site.

Which statements are correct or wrong? Statement 1 is correct, statement 2 is wrong. incorrect Both statements are correct. incorrect Statement 1 is wrong, statement 2 is correct. correct Both statements are wrong. incorrect MC Which statement is NOT CORRECT? RAID level 0 is used if performance is more important than fault tolerance. incorrect RAID level 5 strikes a balance between read and write performance, storage efficiency, and fault tolerance. incorrect To store the same amount of data, RAID 1 needs twice the amount of storage capacity compared to RAID 0. incorrect Block level striping as used in RAID 0 does not increase read performance. correct MC Which statement is CORRECT? If no further statistical information about a predicate is available, the filter factor of that predicate can be estimated by dividing 1 by the number of different values the attribute type can have. correct The filter factor of a predicate is the fraction of rows that contain a missing value for that predicate. incorrect SQL is a declarative language, meaning that the programmer has to specify what data to retrieve and how the data is to be located and retrieved from the physical database files. incorrect Table cardinality is another way of referring to the number of columns in a table. incorrect MC Which statement is NOT CORRECT? A NAS gateway receives file level I/O requests from servers connected to the LAN or WAN and translates these into SCSI block I/O commands to access the external storage devices - this latter connection can be organized by DAS or SAN technology. incorrect Compared to SAN, a NAS is much less expensive and much simpler in soft- and hardware. However, it achieves performance similar to a NAS set-up. correct A SAN is typically best in terms of performance, because it often uses Fibre Channel, the LAN network is freed from storage related traffic, and Fibre Channel compatible storage devices have some onboard intelligence, which allows them to perform certain tasks autonomously, e.g. server-free back-ups. incorrect A DAS does not offer out-of-the-box capabilities for centralized storage management and sharing unused disk capacity across servers. incorrect MC Given 2 tables R and S. Which of the following join strategies is described by the following algorithm:

denote S -> outer table
for every row s in S do {
  for every row r in R do {
    if r(a) = s(b) then join r with s and place in output buffer
  }
} Nested loop join correct Sort-Merge join incorrect None of these joins incorrect Hash join incorrect MC Which statement is NOT CORRECT? Using error correcting codes for fault tolerance requires extra storage space, almost as much as when opting for disk mirroring. correct With bit level data striping, every disk participates in each read or write operation. incorrect It is often more efficient to combine multiple smaller physical disk drives into one larger logical drive because reliability can be improved by introducing some measure of data redundancy. incorrect It is often more efficient to combine multiple smaller physical disk drives into one larger logical drive because having multiple physical drives allows for parallel retrieval, which results in much more improved performance. incorrect MC Which statement is CORRECT? If no further statistical information about a predicate is available, the filter factor of that predicate can be estimated by dividing 1 by the number of different values the attribute type can have. correct Table cardinality is another way of referring to the number of columns in a table. incorrect The filter factor of a predicate is the fraction of rows that contain a missing value for that predicate. incorrect SQL is a declarative language, meaning that the programmer has to specify what data to retrieve and how the data is to be located and retrieved from the physical database files. incorrect MC Given 2 tables R and S. Which of the following join strategies is described by the following algorithm:

Stage 1:
sort R according to r(a)
sort S according to s(b)

Stage 2:
retrieve the first row r of R
retrieve the first row s of S
for every row r in R do {
  while s(b) < r(a) do {
    read the newt row s of S
    if r(a) = s(b) then join r with s and place in output buffer
  }
} None of these join strategies incorrect Nested loop join incorrect Hash join incorrect Sort-Merge join correct