Which of the following database instances are created by default when SQL Server is installed? (Choose two.)
Correct : B, D
The two database instances that are created by default when SQL Server is installed are master and model. Master is a system database that contains the information and settings of the SQL Server instance, such as the configuration, logins, endpoints, databases, etc. Master is essential for the operation and management of the SQL Server instance, and it should be backed up regularly. Model is a system database that serves as a template for creating new user databases. Model contains the default settings and objects, such as tables, views, procedures, etc., that will be inherited by the new user databases. Model can be modified to customize the new user databases according to specific needs or preferences. The other options are either not database instances or not created by default when SQL Server is installed. For example, root is not a database instance, but a term that refers to the highest level of access or privilege in a system; log is not a database instance, but a file that records the changes made by transactions on a database; view is not a database instance, but an object that represents a subset or a combination of data from one or more tables; index is not a database instance, but a data structure that stores the values of one or more columns of a table in a sorted order.Reference:CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.3 Given a scenario, update database systems.
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Which of the following NoSQL database types best categorizes MongoDB?
Correct : A
The NoSQL database type that best categorizes MongoDB is document. Document databases are databases that store and manage data as documents, which are collections of fields and values in formats such as JSON (JavaScript Object Notation) or XML (Extensible Markup Language). Document databases do not use any schema or structure to organize data, but rather use identifiers or indexes to enable flexible and dynamic access to data based on fields or values. Document databases are suitable for storing large amounts of complex or unstructured data that have variable attributes or nested structures. MongoDB is an example of a document database that uses JSON-like documents to store and query data. The other options are either different types of NoSQL databases or not related to NoSQL databases at all. For example, column-oriented databases are databases that store and manage data as columns rather than rows; graph databases are databases that store and manage data as nodes and edges that represent entities and relationships; key-value stores are databases that store and manage data as pairs of keys and values.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.1 Given a scenario, identify common database types.
Which of the following tools is used for natively running a Linux system in Windows?
The tool that is used for natively running a Linux system in Windows is WSL. WSL, or Windows Subsystem for Linux, is a feature that allows users to run a Linux system natively on Windows 10 or Windows Server. WSL enables users to install and use various Linux distributions, such as Ubuntu, Debian, Fedora, etc., and run Linux commands, tools, applications, etc., without requiring a virtual machine or a dual-boot setup. WSL also provides users with interoperability and integration between Linux and Windows, such as file system access, network communication, process management, etc. WSL is useful for users who want to use Linux features or functionalities on Windows, such as development, testing, scripting, etc. The other options are either different tools or not related to running a Linux system in Windows at all. For example, Remote Desktop Protocol (RDP) is a protocol that allows users to remotely access and control another computer or device over a network; SSH, or Secure Shell, is a protocol that allows users to securely connect and communicate with another computer or device over a network; Telnet is a protocol that allows users to interact with another computer or device over a network using a text-based interface.Reference:CompTIA DataSys+ Course Outline, Domain 2.0 Database Deployment, Objective 2.2 Given a scenario, create database objects using scripting and programming languages.
Which of the following NFs is considered the most preferable for relational database design?
Correct : B
The NF (normal form) that is considered the most preferable for relational database design is 3 NF. 3 NF, or Third Normal Form, is a level of normalization that organizes data into tables and columns to reduce redundancy and improve consistency. Normalization is a process that applies a set of rules or criteria to eliminate or minimize the anomalies or problems that may arise from inserting, updating, or deleting data in a database. 3 NF is achieved when a table satisfies the following conditions: - It is in 2 NF (Second Normal Form), which means that every non-key column depends on the whole primary key and not on any subset of it - It has no transitive dependencies, which means that every non-key column depends directly on the primary key and not on any other non-key column 3 NF is considered the most preferable for relational database design because it ensures that each table has only one purpose or theme and that each column has only one value or meaning. This helps avoid data duplication, inconsistency, and update anomalies. The other options are either lower or higher levels of normalization that are either less preferable or less practical for relational database design. For example, 1 NF (First Normal Form) is the lowest level of normalization that requires each column to have atomic values and each row to have a unique identifier; 4 NF (Fourth Normal Form) is a higher level of normalization that requires each table to have no multi-valued dependencies, which means that there are no columns that can have more than one value for the same primary key value; 2 NF (Second Normal Form) is an intermediate level of normalization that requires each non-key column to depend on the whole primary key and not on any subset of it.Reference:CompTIA DataSys+ Course Outline, Domain 1.0 Database Fundamentals, Objective 1.2 Given a scenario, execute database tasks using scripting and programming languages.
Which of the following indexes stores records in a tabular format?
The index that stores records in a tabular format is columnstore. A columnstore index is a type of index that stores and compresses data by columns rather than by rows. A columnstore index can improve the performance and efficiency of queries that perform aggregations, calculations, or analysis on large amounts of data, such as data warehouse or business intelligence applications. A columnstore index can also reduce the storage space required for data by applying various compression techniques, such as dictionary encoding, run-length encoding, bit packing, etc. The other options are either different types of indexes or not related to indexes at all. For example, a non-clustered index is a type of index that stores the values of one or more columns in a sorted order along with pointers to the corresponding rows in the table; a unique index is a type of index that enforces uniqueness on one or more columns in a table; a secondary index is an alternative term for a non-clustered index.Reference:CompTIA DataSys+ Course Outline, Domain 3.0 Database Management and Maintenance, Objective 3.1 Given a scenario, perform common database maintenance tasks.