WGU D426 (MASTER) EXAM WITH
COMPLETE SOLUTION
Database application - ANS-A program that lets business users interact with database
systems.
Database administrator (DBA) - ANS-Secures the DB, manages access, and enforces
availability procedures.
Authorization - ANS-Limits user access to specific tables, columns, or rows.
Business rules - ANS-Rules that keep data consistent with structural and policy
constraints.
Query processor - ANS-Parses queries, optimizes plans, and returns results.
Storage manager - ANS-Executes low-level file operations and uses indexes to locate
data.
Transaction manager - ANS-Ensures ACID execution and recovery from failures.
CRUD: INSERT - ANS-Adds new rows to a table.
CRUD: SELECT - ANS-Retrieves data from a table.
CRUD: UPDATE - ANS-Modifies existing rows in a table.
CRUD: DELETE - ANS-Removes rows from a table.
CREATE TABLE - ANS-Defines a new table with columns and data types.
DROP TABLE - ANS-Deletes a table and all its rows.
ALTER TABLE - ANS-Adds, drops, or modifies columns or constraints of a table.
INT - ANS-Data type for integers.
DECIMAL(M,D) - ANS-Data type for fixed-precision numbers.
VARCHAR(N) - ANS-Data type for variable-length text up to N chars.
, DATE - ANS-Data type for year, month, day.
Tuple - ANS-Ordered list of values; order matters.
Table - ANS-Set of rows with a fixed tuple of columns; rows have no inherent order.
Redundancy - ANS-Repetition of related values in a table.
Candidate key - ANS-Unique and minimal column set; one chosen as primary key.
Non-key column - ANS-Column not part of any candidate key.
Third Normal Form - ANS-If non-key A depends on B, then B must be unique.
Boyce-Codd Normal Form - ANS-If A depends on B, then B must be unique; stronger
than 3NF.
Trivial dependency - ANS-A depends on B when A ⊆ B.
Normalization - ANS-Decompose tables to remove redundancy.
Denormalization - ANS-Merge tables to reintroduce redundancy for performance.
Table structure: heap - ANS-No row order; fastest bulk inserts.
Table structure: sorted - ANS-Rows stored in order of a sort column.
Table structure: hash - ANS-Rows assigned to buckets by a hash function.
Table cluster - ANS-Interleaves related tables in same storage area.
Table scan - ANS-Reads table blocks directly without using an index.
Index scan - ANS-Traverses index to find relevant table blocks.
Hit ratio (selectivity) - ANS-Percent of rows selected by a query predicate.
Binary search in index - ANS-Halves the search space repeatedly to locate entries.
Dense index - ANS-Index entry for every table row.
Sparse index - ANS-Index entry per table block, not per row.
Hash index - ANS-Index that assigns entries to hash buckets.
COMPLETE SOLUTION
Database application - ANS-A program that lets business users interact with database
systems.
Database administrator (DBA) - ANS-Secures the DB, manages access, and enforces
availability procedures.
Authorization - ANS-Limits user access to specific tables, columns, or rows.
Business rules - ANS-Rules that keep data consistent with structural and policy
constraints.
Query processor - ANS-Parses queries, optimizes plans, and returns results.
Storage manager - ANS-Executes low-level file operations and uses indexes to locate
data.
Transaction manager - ANS-Ensures ACID execution and recovery from failures.
CRUD: INSERT - ANS-Adds new rows to a table.
CRUD: SELECT - ANS-Retrieves data from a table.
CRUD: UPDATE - ANS-Modifies existing rows in a table.
CRUD: DELETE - ANS-Removes rows from a table.
CREATE TABLE - ANS-Defines a new table with columns and data types.
DROP TABLE - ANS-Deletes a table and all its rows.
ALTER TABLE - ANS-Adds, drops, or modifies columns or constraints of a table.
INT - ANS-Data type for integers.
DECIMAL(M,D) - ANS-Data type for fixed-precision numbers.
VARCHAR(N) - ANS-Data type for variable-length text up to N chars.
, DATE - ANS-Data type for year, month, day.
Tuple - ANS-Ordered list of values; order matters.
Table - ANS-Set of rows with a fixed tuple of columns; rows have no inherent order.
Redundancy - ANS-Repetition of related values in a table.
Candidate key - ANS-Unique and minimal column set; one chosen as primary key.
Non-key column - ANS-Column not part of any candidate key.
Third Normal Form - ANS-If non-key A depends on B, then B must be unique.
Boyce-Codd Normal Form - ANS-If A depends on B, then B must be unique; stronger
than 3NF.
Trivial dependency - ANS-A depends on B when A ⊆ B.
Normalization - ANS-Decompose tables to remove redundancy.
Denormalization - ANS-Merge tables to reintroduce redundancy for performance.
Table structure: heap - ANS-No row order; fastest bulk inserts.
Table structure: sorted - ANS-Rows stored in order of a sort column.
Table structure: hash - ANS-Rows assigned to buckets by a hash function.
Table cluster - ANS-Interleaves related tables in same storage area.
Table scan - ANS-Reads table blocks directly without using an index.
Index scan - ANS-Traverses index to find relevant table blocks.
Hit ratio (selectivity) - ANS-Percent of rows selected by a query predicate.
Binary search in index - ANS-Halves the search space repeatedly to locate entries.
Dense index - ANS-Index entry for every table row.
Sparse index - ANS-Index entry per table block, not per row.
Hash index - ANS-Index that assigns entries to hash buckets.
