Q&A Hero

Q: When accessing table structure, and determining the number and types of columns in a table, how can you control how many rows are returned?

Q: When assessing table structure, how do you determine the number and types of columns in a table?

Q: When accessing table structure, how do you determine how many rows are in a table?

Q: Describe the steps in assessing table structure when you are given a set of tables and asked to construct a new database to store the existing data.

Q: Reviewing the work done on a table that was created using existing data from multiple sources, you find that a column named Remarks has been included, and it is populated with inconsistent and verbose verbal data. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: The SQL keyword IS NULL can be used to help ________. A) count the number of columns in a table B) count the number of rows in a table C) count the number of null values in a column D) count the number of values in a column

Q: To check for null values in a column in a table, use the SQL phrase ________. A) IS B) IS NOT C) IS NULL D) COUNT(NULL)

Q: A null value can indicate which of the following conditions? A) The value is incorrect. B) The value is appropriate but unknown. C) The value has been updated. D) The value can never be changed.

Q: A missing value is called a(n) ________. A) empty value B) null value C) missing value D) deleted value

Q: Reviewing the work done on a table that was created using existing data from multiple sources, you are likely to find that some data values that were provided were never entered into the table. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: When a table is created using existing data, you are likely to find that some data values have never been provided because any value there would be inappropriate. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: When a table is created using existing data from multiple sources, you are likely to find that some data values have never been provided because the values are not known. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: The problem of misspelled data entries is really the same as ________. A) the multivalue, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: You are creating a PRODUCT table using existing data from multiple sources. Examining the data, you find that you have "large red hat", "large hat, red", "red hat large" and "hat, large, red." This is an example of ________. A) the multivalue, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: When a table is created using existing data from multiple sources, you are likely to find that the different sources code data in slightly different ways. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: A form of multivalued dependency is found in ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: A table with columns PhoneNumber01, PhoneNumber02, and PhoneNumber03 is likely to have ________. A) the multivalue, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem

Q: An advantage of denormalization is ________. A) faster updating B) faster querying C) faster copying of data D) faster design

Q: ________ is the process of joining two or more tables and storing the result as a single table. A) Querying B) Normalization C) Denormalization D) Updating

Q: For a number of reasons, ________ is not often an advantage for a read-only database. A) updating B) normalization C) denormalization D) Both A and B are correct

Q: Read-only databases are used for ________. A) updating B) querying C) data entry D) user account management

Q: Unlike the anomalies from functional dependencies, the anomalies from ________ are so serious that they should always be eliminated. A) general purpose remarks columns B) sales orders and line items C) association patterns D) multivalued dependencies

Q: A classic example of unneeded normalization is when we are dealing with ________. A) ZIP codes B) sales orders and line items C) association patterns D) multivalued dependencies

Q: The defining characteristic of BCNF is that a table is in BCNF if ________. A) all rows are unique B) all columns are consistent C) the primary key is a candidate key D) all determinants are candidate keys

Q: Anomalies caused by functional dependencies can be eliminated by putting tables into ________. A) 1NF B) 2NF C) 3NF D) BCNF

Q: The presence of one or more foreign keys in a relation prevents ________. A) the elimination of modification anomalies B) the elimination of duplicated data C) more complex SQL for multitable subqueries and joins D) Both A and B are correct

Q: The disadvantages of normalization include ________. A) the elimination of modification anomalies B) the elimination of duplicated data C) more complex SQL for multitable subqueries and joins D) Both A and B are correct

Q: The advantages of normalization include ________. A) the elimination of modification anomalies B) the elimination of duplicated data C) more complex SQL for multitable subqueries and joins D) simpler SQL queries

Q: You have been given two tables, CUSTOMER and SALE. You want to check the referential integrity constraint: SALE.CustomerNumber must exist in CUSTOMER.CustomerNumberYou run the following SQL query:SELECT CustomerNumberFROM SALEWHERE CustomerNumber NOT IN (SELECT CustomerNumber FROM CUSTOMER);What is shown in the results of this query?A) All values of CustomerNumber that match the constraint.B) All values of CustomerNumber that violate the constraint.C) All values of CustomerNumber whereSALE.CustomerNumber = CUSTOMER.CustomerNumber.D) All values of Customer number that are in CUSTOMER but not in SALE.

Q: The SQL keyword TOP ________. A) limits the number of columns retrieved from a table B) limits the number of rows retrieved from a table C) limits the number of tables retrieved from a database D) A and C

Q: To limit the number of rows retrieved from a table, use the SQL construct ________. A) SELECT * B) SELECT TOP n * C) SELECT COUNT(TOP n) D) SELECT COUNT(*)

Q: The SQL function COUNT ________. A) counts the number of columns in a table B) counts the number of rows in a table C) counts the number of tables in a database D) counts the number of updates to a database

Q: To count the number of rows in a table, use the SQL construct ________. A) SELECT * B) SELECT TOP n * C) SELECT COUNT(TOP n) D) SELECT COUNT(*)

Q: During the second step of assessing table structure, you are trying to determine ________. A) relationships B) candidate keys C) updatability D) efficiency

Q: During the second step of assessing table structure, you are trying to determine ________. A) multivalued dependencies B) data types C) missing values D) subqueries

Q: The second step in assessing table structure includes ________. A) counting rows B) examining columns C) examining data values D) A and B

Q: The first step in assessing table structure includes ________. A) counting rows B) examining columns C) examining data values D) Both A and B are correct

Q: When you are given a set of tables and asked to create a database to store their data, the first step is to ________. A) assess the existing tables' structure and content B) design the database structure C) create one or more new tables D) move the data into the new database

Q: If you see a column name Notes, it is likely that this is a general-purpose remarks column.

Q: The problem with a general-purpose remarks column is that the data it contains are likely to be verbal, inconsistent, and stored in a verbose manner.

Q: General-purpose remarks columns rarely contain important data.

Q: The SQL IS NULL keyword can be used to count the number of nulls in a column.

Q: Most DBMS products will let you define a primary key on a column that contains null values.

Q: A null value in a column may indicate that there is an appropriate value for that attribute, and although the value is known, no one has entered the value into the database.

Q: A null value in a column may indicate that there is an appropriate value for that attribute, but it is unknown.

Q: A null value in a column may indicate that there is no appropriate value for that attribute.

Q: Null values are a problem because they are ambiguous.

Q: A missing value is called a null value.

Q: You are creating a BOAT table using existing data from multiple sources, and you find that you have "power boat blue", "boat, power, blue" and "blue power boat" as data values for the same column. This is an example of the inconsistent values problem.

Q: The problem of misspelled data entries is an entirely different problem than the inconsistent values problem.

Q: An inconsistent values problem is created when different users have coded the same data entries differently.

Q: When you are creating a database from existing data, you will have only minor problems with inconsistent values.

Q: If you have a table with a set of columns named "Child01", "Child02" and "Child03", the table is likely to have the multivalued, multicolumn problem.

Q: One situation created by the multivalued, multicolumn problem is that the maximum number of data values for an attribute is limited.

Q: The multivalued, multicolumn problem occurs when a set of columns are used to store data that should actually be in one column.

Q: Multivalued dependencies show up under a different name as the multivalued, multicolumn problem.

Q: Read-only databases often use several copies of a set of the same data, where each copy is modified for a specific use.

Q: Read-only databases seldom use more than one copy of a set of the same data.

Q: Denormalization is simplejoin the data together and store it in a table.

Q: Denormalization reduces the complexity of the SQL statements needed in an application to read required data.

Q: Denormalization is the process of joining previously normalized tables back together.

Q: Normalization is an advantage for a read-only database.

Q: Design guidelines and priorities are the same whether you're working with an updatable database or a read-only database.

Q: Read-only databases are often updated.

Q: Creating a read-only database is a job often given to beginning database professionals.

Q: To eliminate multivalued dependencies, normalize your tables so that they are all in BCNF.

Q: Writing SQL subqueries and joins against normalized tables is simple compared to the code that must be written to handle anomalies from multivalued dependencies.

Q: Multivalued dependencies create anomalies so serious that multivalued dependencies must always be eliminated.

Q: United States ZIP codes are a classic example of unneeded normalization.

Q: SQL statements that can be used to create referential integrity statements for normalized tables are created during the normalization process.

Q: The SQL DELETE TABLE statement can be used to remove unneeded tables after the normalized tables are created and populated.

Q: The SQL INSERT statement can be used to populate normalized tables.

Q: A defining requirement for BCNF is that every determinant must be a candidate key.

Q: Relations in BCNF have no modification anomalies in regard to functional dependencies.

Q: Relations are sometimes left unnormalized to improve performance.

Q: Normalization requires applications to use more complex SQL since they will need to write subqueries and joins to recombine data stored in separate relations.

Q: The presence of one or more foreign keys in a relation means that we cannot eliminate duplicated data in that table.

Q: Normalization eliminates modification anomalies and data duplication.

Q: Database design varies depending on whether you're building an updatable database or a read-only database.

Q: The elimination of modification anomalies and the reduction of duplicated data are advantages of normalization.