CS 430 Midterm #2 Study Guide
Consider the following relation. Check all the answers below that hold for this table. A | B | C | D a1 | b1 | c1 | d1 a1 | b3 | c1 | d2 a3 | b1 | c1 | d3 a2 | b7 | c1 | d5 * D -> ABC * A -> BC * ABD -> C * BC -> AD * B -> A * AB -> CD * AB -> D
* D -> ABC * ABD -> C * AB -> CD * AB -> D
Which of the following are common techniques used to develop algorithms for each relational operator evaluation? * Indexing - using an index to examine just those tuples that satisfy the condition * Normalization - providing normalization of the data as the query is processed * Iteration - examining all tuples in an input table, one after another * Selection operations - selecting only those operations that can run efficiently * Partitioning - decomposing an operation into a less expensive collection of operations.
* Indexing - using an index to examine just those tuples that satisfy the condition * Iteration - examining all tuples in an input table, one after another * Partitioning - decomposing an operation into a less expensive collection of operations.
Which of the following are true about B+ tree-based indexing? - The data is contained within the nodes as well as in the leafs. - Finding the correct leaf page is faster than a binary search. - The lowest level of the tree - called the leaf level - contains the data entries. - It is an index structure that ensures that all paths from the root to a leaf in a given tree are of the same height. - Finding the correct leaf page is done in nlogn time, where time is measured by node accesses.
- Finding the correct leaf page is faster than a binary search. - The lowest level of the tree - called the leaf level - contains the data entries. - It is an index structure that ensures that all paths from the root to a leaf in a given tree are of the same height.
Which of the following are true about B+ tree index files? - Insert / delete at logFN cost where F = fanout and N = # leaf pages. - Each node contains exactly 2d entries. d is called the order of the tree. - Each node contains d - Maximum 50% occupancy (except for root). - B+ tree is the most widely used index.
- Insert / delete at logFN cost where F = fanout and N = # leaf pages - Each node contains d - B+ tree is the most widely used index.
Match the disk movement term to its appropriate description. - Seek Time - Rotational delay - Transfer time
- Seek Time: moving arms to position the disk head on track - Rotational delay: time for the block to rotate under the head - Transfer time: time to move the data to/from the surface
Match the RAID level with its appropriate description. RAID 0 RAID 1 RAID 1+0 RAID 5 provides redundancy by mirroring each of the drives provides a striped set from a set of mirrored drive improves performance by striping the files across multiple drives, NO parity allows a single drive to fail without data loss by providing block level parity, does NOT provide P+Q redundancy
-RAID 0: improves performance by striping the files across multiple drives, NO parity -RAID 1: provides redundancy by mirroring each of the drives -RAID 1+0: provides a striped set from a set of mirrored drive -RAID 5: allows a single drive to fail without data loss by providing block level parity, does NOT provide P+Q redundancy
Match the operation to its effect. Union operation Set-difference operations Cartesion-product operation Rename operations
-Union operation: binary operation that returns the values present in both tables -Set-difference operations: finds tuples that are in one relation but not in another -Cartesion-product operation: combines information from any two relations -Rename operations: provides a unique identifier to the results of a relational algebra operation
Under what circumstances must a database index be updated? A record is inserted into a databse. A record is deleted from the database. A record is updated in the database. A security key is added to the database.
-a record is inserted into a database -a record is deleted from the database
Which of the following relational algebra operations are binary and which are unary? select project rename Cartesian product assignment set difference divide natural join left outer join right outer join full outer join
-select: unary -project: unary -rename: unary -Cartesian product: binary -assignment: binary -set difference: binary -divide: binary -natural join: binary -left outer join: binary -right outer join: binary -full outer join: binary
For a set of 100 data records with 5 fields per record, how many clustered indexes can there be? 1 5 100 500
1 There can only be one clustered index for any file.
Match the steps to insert a data entry into a B+ tree to their order: If room in L, put data entry into L; done If necessary, split index node recursively. Split L, redistribute entries evenly, copy up middle key Insert index entry pointing to L2 into parent of L Find the correct leaf L
1 - Find the correct leaf L 2 - If room in L, put data entry into L; done 3 - Split L, redistribute entries evenly, copy up middle key 4 - Insert index entry pointing to L2 into parent of L 5 - If necessary, split index node recursively.
Match the elements below to their position in the storage-device hierarchy, according to their speed. 1 - Fastest, 5 - Slowest flash memory magnetic tapes cache main memory disk
1 - cache 2 - main memory 3 - flash memory 4 - disk 5 - magnetic tapes
Match the elements below to their position in the storage-device hierarchy, according to their cost. 1 2 3 4 5 6
1 - cache 2 - main memory 3 - flash memory 4 - magnetic disk 5 - optical disk 6 - magnetic tapes
Match the operation while deleting a data entry from a B+ tree to its order of sequence. Find Leaf L where entry exists Recursively merge index node where necessary If L falls below d, try to redistribute If L falls below d and redistribution fails, merge L with sibling Remove entry, replace index if necessary
1) Find Leaf L where entry exists 2) Remove entry, replace index if necessary 3) If L falls below d, try to redistribute 4) If L falls below d and redistribution fails, merge L with sibling 5) Recursively merge index node where necessary
A B+ tree with a typical order of 100 and fill factor of 2/3 (i.e. fanout of 133), with a height of 4 can handle how many records? 133^3 133 * 4 = 532 4^133 133^4 3^133
133^4
How many disk heads are there in a disk drive that has 4 double-sided platters, 200 cylinders, and 2000 tracks? 10 8 1 16 4
8
Consider the relation R with attributes: A, B, C, D, E, and F. Let S be a set of functional dependencies in R such that S = { A -> B, CD -> E, C -> A}. Which of these attributes are in the closure of {A, B}+? D E C F A B
A B
Consider the relation R with attributes: A, B, C, D, E, and F. Let S be a set of functional dependencies in R such that S = { A -> B, CD -> E, C -> D}. Which of these attributes are in the closure of {A, C, F}+? A B C D E F
A B C D E F
A relation schema R is in third normal form with respect to set F of functional dependencies, if for all functional dependencies in F+ of the form A -> B where A is a subset of R, B is an attribute of R, and at least on e of the following holds: * A -> B is a trivial functional dependency * A is a superkey for R. * B is part of a key for R. * B is a superkey for R. * A is part of a key for R.
A -> B is a trivial functional dependency A is a superkey for R. B is part of a key for R.
A relation schema R is in BCNF with respect to a set F of functional dependencies if, for all functional dependencies in F+ of the form A -> B, where A is a subset of R, B is a subset of R - and at least one of the following hold: A and B are both atomic. A -> B is an atomic dependency on R. A -> B is a trivial functional dependency (that is, B is a subset of A) A is a superkey for schema R. B is a superkey for schema R
A -> B is a trivial functional dependency (that is, B is a subset of A) A is a superkey for schema R.
The primary difference between a B tree indices and a B+ tree indices is which of the following? A B-tree eliminates the redundant storage of search-key values. A B+-tree eliminates the redundant storage of search-key values. A B-tree eliminates the redundant storage of primary keys. A B+-tree eliminates the redundant storage of primary keys. A B-tree eliminates primary keys.
A B-tree eliminates the redundant storage of search-key values.
When a file is organized so that the ordering of data records is the same as or close to the ordering of data entries in some index, we say that is: A typed index. A primary index. A secondary index. A sorted index. A clustered index.
A clustered index.
Which of the following is true about primary and secondary indexes? A primary index is the main index field of an index file, a secondary index is all other fields in the index file. A primary index is the main index field of an index file, a secondary index is the rid pointing to the actual record. A primary index is one that contains the primary key, a secondary index contains additional fields as well as the primary key. A primary index is one that contains file pointers, a secondary index describes all other file pointers. A primary index is one that does not allow duplicates, a secondary index is one that does.
A primary index is one that does not allow duplicates, a secondary index is one that does.
The unit of transfer betweeen disk and main memory is which of the following? A set of sectors A cylinder A track A platter A sector
A set of sectors
Consider the following relation. Check all the answers below that hold for this table. A | B | C | D a1 | b1 | c1 | d1 a2 | b3 | c1 | d2 a3 | b1 | c1 | d3 a2 | b7 | c1 | d5 * ABD -> C * D -> ABC * AB -> D * AB -> CD * B -> A * A -> BC * BC -> AD
ABD -> C D -> ABC AB -> D AB -> CD
The time it takes for a particular hashing or indexing technique to find a particular data item, or set of items. Deletion time Ordered index Secondary index Space overhead Access type Access time Search key Insertion time Hash index Skew
Access time
Static hashing is done by performing which of the following? Applying a hash function h to the search key to identify the bucket to which it belongs and then searching this bucket. Applying a hash function h to identify the directory entry then following the chain of buckets to the correct one. Using the pointer obtained from the search key to identify the data page which is then hashed. Using the pointer obtained from the search key and applying the hashing function to the pointer. Applying the hash function to the data record and using it to find the record.
Applying a hash function h to the search key to identify the bucket to which it belongs and then searching this bucket.
Consider the following relation. Check all the answers below that hold for this table. A | B | C | D a1 | b1 | c1 | d1 a1 | b3 | c1 | d2 a3 | b2 | c1 | d3 a2 | b7 | c1 | d5 * B -> ACD * B -> A * A -> CD * AC -> BD * A -> BC * AB -> D * D -> ABC
B -> ACD B -> A AB -> D D -> ABC
Because all the pages cannot be brought into memory at the same time, the DBMS must bring pages into main memory as they are needed and, in the process, decide what existing page in main memory to replace to make room for the new page. Which architecture layer of a DBMS is responsible for determining which page to replace? Buffer manager Disk manager Page manager Transaction manager File and Access manager
Buffer manager
Which of the following are techniques used by the buffer manager to address all the disk blocks? Buffer replacement strategy. Disk striping. Forced output of blocks. Pinned blocks. Disk mirroring.
Buffer replacement strategy. Forced output of blocks. Pinned blocks.
Consider the relation R with attributes: A, B, C, D, E, and F. Let S be a set of functional dependencies in R such that S = { A -> B, CD -> E, C -> D}. Which of these attributes are in the closure of {C, F}+? C E B F A D
C E F D
Which of the following accurately describes the following: ρ(R1, πnameσage=23(Employees)) Create a relation instance called R1 that contains the null set. Create a relation instance called R1 containing the names of all employees that are 23 years old. Create a relation instance called R1 containing all the fields of Employee that have employees that are 23 years old. Create a relation instance called π that is the union of R1 and the employees that are 23 years old.
Create a relation instance called R1 containing the names of all employees that are 23 years old.
Which of the following best describes the 2 parts of the representation of a record with variable-length attributes? Data describing the fixed length attributes Data for variable length attributes Initial part with fixed length attributes Array of records, each pointing to an offset.
Data for variable length attributes Initial part with fixed length attributes
The time it takes for a particular hashing or indexing technique to delete a data item. Deletion time Ordered index Secondary index Space overhead Access type Access time Search key Insertion time Hash index Skew
Deletion time
The key attribute of a hashing function is which of the following? * The ability of the function to grow the table appropriately. * Even distribution of the entries throughout the table. * Even distribution of the sizes of the search keys. * The ability to work recurrence relations. * The ability for the function to work with minimal memory.
Even distribution of the entries throughout the table.
The key attribute of a hashing function is which of the following? Even distribution of the entries throughout the table. The ability to work recurrence relations. Even distribution of the sizes of the search keys. The ability of the function to grow the table appropriately. The ability for the function to work with minimal memory.
Even distribution of the entries throughout the table.
A conjunction of conditions of the form where op is a comparison operator is said to be in Bryce Codd Normal Form.
False
A database design is in BCNF if one member of the set of relation schemas that constitutes the design is in BCNF.
False
A marginalized temporary table is one that is created to pass intermediate tables between operators.
False
A primary index is one that includes the primary key, indexes that include only other candidate keys are called secondary indexes.
False
A search key is the same as a candidate key.
False
BCNF can always be achieved without sacrificing losslessness or dependency preservation.
False
If we are inserting a data entry into a bucket in a static hashing table and there is no space in the bucket, we split the bucket and put the entry into the new bucket.
False
If you perform a relational algebra cross-product on two relation instances that contain exactly the same attributes (and their associated domains) and exactly the same values in those relation instances, you will get the same result as performing a natural join on those relation instances.
False
Relational schemas and other metadata about relations are stored in a structure called system cache.
False
The ability to double the directory by simply copying the directory to the lower part is accomplished because we are using the most significant bits.
False
The main advantage to a static hashing schemes is that the number of buckets is variable and memory allocation becomes simplified.
False
The natural-join algorithm (also called the sort-merge-join algorithm) can be used to compute natural joins and equi-joins.
False
The project operation is a tertiary operation that returns its argument relation, the predicate is was called with, and the lead attribute.
False
Two scan algorithms to implement a selection operation are a linear search and a bubble search.
False
Howwould you translate the following relational algebra expression: πperson-name(σcompany-name="Alpha"(works)) None of the answers provided Find the names of all companies who employee a person named Alpha. Find the names of all employees who have managers named Alpha. Find the names of all employees who work for the company named Alpha. Find the names of all managers who work for the company named Alpha.
Find the names of all employees who work for the company named Alpha.
An indexing technique based on a uniform distribution of values across a range of buckets. Deletion time Ordered index Secondary index Space overhead Access type Access time Search key Insertion time Hash index Skew
Hash index
A global depth indicator N in an extendible hashing scheme is used to identify which of the following? Identifies that there are 2**N number of entries in the directory. Identifies that there are N number of data entries. Identifies that there are 2**N number of data entries. Identifies that there are N number of entries in the directory.
Identifies that there are 2**N number of entries in the directory.
Which of the following defines a functional dependency? - If there were a schema A, two primary keys are necessary to identify it. - If there exists a schema A, primary key B is a candidate key. - If there were a schema (A,B), then A is able to serve as a primary key. - For schema B, primary key A exists. - For schema A, primary key B exists.
If there were a schema (A,B), then A is able to serve as a primary key.
A query evaluation plan consists of which of the following? Character representation of the SQL language. Implementation methods to use for each relational operator. An extended relational algebra tree with additional annotations at each node. Selection properties.
Implementation methods to use for each relational operator. An extended relational algebra tree with additional annotations at each node.
Which of the following are NOT part of the metadata stored in a system catalog? Index values. Index size. Index name. Index structure. Index height.
Index values.
The time it takes for a particular hashing or indexing technique to insert a new data item. Access time Insertion time Deletion time Space overhead Access type Search key Ordered index Hash index Skew Secondary index
Insertion time
Which buffer replacement policy is optimal for a database system in all scenarios? Least Recently Used (LRU) It depends - no one strategy is always optimal. Toss Immediately (TI) Most Recently Used (MRU)
It depends - no one strategy is always optimal.
What is a materialized table used for? All of the above. It is a piplelined table used to pass tuples between operations It is a temporary table used to pass tuples between operations. It is a pipelined table used to pass metadata between operations. It is a temporary table used to pass metadata between operations.
It is a temporary table used to pass tuples between operations.
The two most common tertiary storage media are: Main memory Magnetic tapes Magnetic disks Optical disks Flash memory
Magnetic tapes Optical disks
Which of the following are factors to be taken into account when choosing a RAID level? Monetary cost of extra disk-storage requirements. Performance requirements in terms of number of I/O operations. Performance when a disk has failed. Performance during a disk rebuild Improvement of MTBF of a disk unit.
Monetary cost of extra disk-storage requirements. Performance requirements in terms of number of I/O operations. Performance when a disk has failed. Performance during a disk rebuild
An indexing technique based on a sorted ordering of the values. Access time Search key Ordered index Access type Insertion time Space overhead Secondary index Deletion time Skew Hash index
Ordered index
Which of the following are steps involved in processing a query? Representation. Compilation. Parsing and translation. Evaluation. Optimization.
Parsing and translation. Evaluation. Optimization.
Which of the following are factors to be taken into account when choosing a RAID level? Performance when a disk has failed. Performance during a disk rebuild Improvement of MTBF of a disk unit. Monetary cost of extra disk-storage requirements. Performance requirements in terms of number of I/O operations.
Performance when a disk has failed. Performance during a disk rebuild Monetary cost of extra disk-storage requirements. Performance requirements in terms of number of I/O operations.
Match the terms associated with queries to its definition. Query language Relational algebra
Query language: a specialized language in which queries can be posed Relational algebra: a formal query language based on a collection of operators manipulating relations
BLANK refers to the range of activities involved in extracting data from a database.
Query processing
The key advantage of using a B+ tree for an index file as opposed to a hashing scheme is which of the following? Range searches Ascending keys Duplicate keys Equality searches Descending keys
Range searches
Pipelining is important in an execution plan because of which of the following? Reduces the cost by streamling the operations in the correct order. Reduces the cost by using the vector processor in a chipset to perform operations one after another. Reduces the cost by creating temporary tables to use. Reduces the cost by passing the tables directly from one operator to another.
Reduces the cost by passing the tables directly from one operator to another.
Which of the following are methods to improve reliability? Striping. Redundant arrays of independent disks (RAID). Improving MTBF. Redundancy. Mirroring.
Redundant arrays of independent disks (RAID). Improving MTBF. Redundancy. Mirroring.
Match each of the following functional dependency rules of inference with the name of the Armstrong Axiom or Implication to which it belongs: - If Y is a subset of X, then X -> Y - If X -> Y and Y -> Z, then X -> Z - If X -> Y and Z is a set of attributes, then XZ -> YZ (or XunionZ -> YunionZ) - If X -> Y and X -> Z, then X-> YZ - If X-> YZ, then X -> Y and X -> Z
Rule of Reflexity: If Y is a subset of X, then X -> Y Rule of Transitivity: If X -> Y and Y -> Z, then X -> Z Rule of Augmentation (Unions):If X -> Y and Z is a set of attributes, then XZ -> YZ (or XunionZ -> YunionZ) Rule of Union (Additive): If X -> Y and X -> Z, then X-> YZ Rule of Decomposition (Projection): If X-> YZ, then X -> Y and X -> Z
Any attribute or set of attributes with which a file may locate a record or set of records. Insertion time Deletion time Space overhead Secondary index Search key Access time Skew Access type Hash index Ordered index
Search key
A type of dense index, with an index entry for every search-key value and a pointer to every record in the file, where the records pointed to by successive values in the index are not stored sequentially. - Secondary index - Hash index - Search key - Space overhead - Access type - Deletion time - Ordered index - Skew - Insertion time - Access time
Secondary index
Match the operations to their effect. Set-intersection operation Natural join operation Division operation Assignment operation
Set-intersection operation: a more convenient way to write r-(r-s) Natural join operation: a binary operation that allows us to combine certain selections and a Cartesian-product into a single operation Division operation: suitable to queries that include phrase "for all" Assignment operation: assigns parts of a relational-algebra expression to temporary relation variables
When some hash buckets are assigned more records than are others, and a bucket may overflow even as other buckets still have space, it is called ________________. Access time Insertion time Deletion time Space overhead Access type Search key Ordered index Hash index Skew Secondary index
Skew
The additional space occupied by an index structure for a particular hashing or indexing technique. Deletion time Search key Hash index Access time Access type Space overhead Secondary index Insertion time Skew Ordered index
Space overhead
Which of the following best describes the advantage of hashing over a tree structure for indexing ? Storing indexes in hash structures could result in smaller keys. Storing indexes in hash structures could result in less depth to the tree. Storing indexes in hash structures could result in less disk I/Os. Storing indexes in hash structure could result in less fanout to the tree. Storing indexes in hash structures could result in better range searches.
Storing indexes in hash structures could result in less disk I/Os.
Which of the following is true about tree-structured indexing techniques? Not good for equality searches or range searches. Supports equality searches but not range searches. Good for sliding window searches, not for equality or range. Support both range searches and equality searches. Supports range searches but not equality searches.
Support both range searches and equality searches.
We say that a relation schema R is in first normal form if: - The domains of all attributes of R are non-atomic. - The domains of all attributes of R are atomic. - The schema is atomic. - The schema is non-atomic. - The primary key of R is non-atomic.
The domains of all attributes of R are atomic.
The average number of children in a B+ tree is called what? The fan-out of the tree. The depth of the tree. The height of the tree. The order of the tree. The significance of the tree.
The fan-out of the tree.
Match the type of data storage to its definition: Cache
The fastest and most costly form of storage.
Which of the following about a database table are stored in the system catalog? The integrity constraints on the table The JDBC connector information Attribute name and type for each attribute in the table The file structure for the table The name of the table
The integrity constraints on the table Attribute name and type for each attribute in the table The file structure for the table The name of the table
Both the global and the local depth use the value to identify which of the following? * The degree of difficuty required by the hash function. * The value to be given to the hash function. * The number of iterations the hash function is to run. * The number of bits of the value returned from the hash table to use.
The number of bits of the value returned from the hash table to use.
Match the type of data storage to its definition: Magnetic-disk storage
The primary medium for long-term on-line storage of data.
The policy that is used to choose and unpinned page to be swapped out is called what? The timing policy, such as SCAN and CSCAN. The swap policy used for thrashing. The replacement policy, such as LRU and clock. The buffer policy, such as free behind and look ahead. The write policy, used for write-ahead logging.
The replacement policy, such as LRU and clock.
In an extendible hashing scheme, the directory structure is grown when which of the following is true? The size of the local depth indicator exceeds the global indicator before the insert. The size of the local depth indicatory exceeds the global indicator after the insert. The size of the global depth indicator exceeds the local indicator before the insert. The size of the global depth indicator exceeds the local indicator after the insert.
The size of the local depth indicatory exceeds the global indicator after the insert.
Match the type of data storage to its definition: Main memory
The storage medium used for data that is available to be operated on.
Which of the following is the responsibility of the query optimizer? To identify executed queries. To identify an efficient execution plan. To act as a locking manager. To perform transactional management.
To identify an efficient execution plan.
A decomposition is a lossless decomposition if for all legal database instances we project r onto R1 and R2, compute the natural join of the projection results, and we get back exactly r.
True
A file is a collection of pages each containing a collection of records. Support must include inserts, deletes, modifies, and reads among other operations.
True
A functional dependency is a form of an integrity constraint.
True
A range search is the concept of finding all records where the seach key value is less than some value and/or greater than another value.
True
An access path is a way of retrieving tuples from a table and consists of either 1) a file scan or 2) and index plus a matching selection condition.
True
An item in the select list can be in the form of expression AS column_name, where expression is any arithmetic or string expression.
True
Axioms, or rules of inference, provide a simpler technique for reasoning about functional dependencies.
True
Division is rarely implemented as a distinct operator in DBMS systems.
True
Dynamic hashing techniques allow the hash function to be modified dynamically to accommodate the growth or shrinkage of the database.
True
Extendible hashing schemes solve the problems of a static hash scheme by implementing a directory of pointers to buckets and growing the directory appropriately.
True
For each view, the system catalog stores the view name and the definition of the view.
True
If a relation r is legal under a set F of functional dependencies, we say that r satisfies F.
True
If the evaluation of a query requires repeated passes to accomplish the partitioning it is called recursive partitioning.
True
In a page format that consists of packed fixed length records, free space is contiguous. In a page format that consists of unpacked fixed length records, free space can be non-contiguous.
True
In general, the goal of a relational database design is to generate a set of relation schemas that allows us to store information without unnecessary redundancy and yet allows us to retrieve information easily.
True
It is always possible to decompose a relation into 3NF form that is both lossless join and dependency preserving.
True
One of the problems with a static hashing scheme is that long overflow chains develop.
True
Several operations in a query plan may be grouped together in a pipeline in which each of the operations starts working on its input tuples even as they are being generated by another operation.
True
System catalogs are stored as as a collection of tables.
True
The buffer manager is responsible for bringing a page into RAM, and the page cannot be removed from RAM until released by the requestor(s).
True
The select operation selects tuples that satisify a given predicate.
True
When building an access path, an index matches a selection criteria if the index can be used to retrieve just the tuples that satisfy the condition.
True
When using a heap file organization, any record can be placed anywhere in the file where there is space for the record.
True
When choosing a hash function to assign search key values to buckets, the function should have which of the following qualities? Normalized distribution. Uniform distribution. Exponential distribution. Random distribution. Linear distribution.
Uniform distribution. Random distribution.
Match the type of data storage to its definition: Tape Storage
Used primarily as a backup storage medium.
Index structures are referred to as BLANK, since they provide a path through which data can be located and accessed.
access paths
The read-write heads of all the tracks are mounted on a single assembly called a disk BLANK. sector read-write head track cylinder platter arm spindle
arm
A B+ tree index takes the form of a BLANK tree in which every path from the root of the tree to a leaf of the tree is of the same length.
balanced
The set of all functional dependencies that can be inferred give the set F, denoted by F+ is called the BLANK of set F
closure
The ith tracks of all the platters together are called the ith ______________. cylinder platter read-write head track arm spindle sector
cylinder
Match the operations to their effect. * Outer join
extension of the join operation to deal with missing information.
Sorting of relations that do not fit in memory is called BLANK sorting.
external
In query processing, the BLANK is the lowest-level operator to access data.
file scan
If we wish to constrain ourselves to relations on schema R that satisfy a set F of functional dependencies, we say that F BLANK on R.
holds
Each disk ______________ has a flat circular shape. - platter - track - cylinder - spindle - arm - read-write head - sector
platter
A sequence of primitive operations that can be used to evaluate a query is called a BLANK plan.
query-evaluation
The ______________ stores information on a sector magnetically, and there is one for each side of each platter of a disk. arm sector platter track spindle read-write head cylinder
read-write head
The ______________s are kept as close as possible to the disk surface to increase the recording density. cylinder sector arm read-write head track platter spindle
read-write head
A ______________ is the smallest unit of information that can be read from or written to the disk. read-write head spindle track platter sector cylinder arm
sector
The disk platters are mounted on a ______________. - cylinder - arm - spindle - track - platter - sector - read-write head
spindle
Match the operations to their effect. * Aggregate Function
takes a collection of values and returns a single value as a result.
The surface of a disk is logically divided into concentric ______________s. read-write head arm sector platter cylinder spindle track
track
Some functional dependencies are said to be BLANK because they are satisfied by all relations.
trivial
