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Database Structures and Querying Flashcards
CompTIA DataX DY0-001 (V1) Flashcards
| Front | Back |
| What are database constraints | Rules enforced on data to ensure accuracy and consistency. |
| What character is typically used to denote wildcards in SQL LIKE queries | %. |
| What does SQL DISTINCT keyword do | Removes duplicate values in the result set. |
| What does SQL stand for | Structured Query Language. |
| What does the SQL clause WHERE do | Filters records based on a specified condition. |
| What does the SQL command DELETE do | Removes data from a table. |
| What does the SQL command INSERT do | Adds new rows to a table. |
| What does the SQL command SELECT do | Retrieves data from a table. |
| What does the SQL command UPDATE do | Modifies existing data in a table. |
| What does the SQL GROUP BY clause do | Aggregates data based on specified columns. |
| What does the SQL HAVING clause do | Applies conditions to groups created by GROUP BY. |
| What is a composite key in a database | A key consisting of two or more columns that uniquely identify a record. |
| What is a data warehouse | A central repository for storing large volumes of business data for analysis. |
| What is a foreign key in a database | A field in one table that links to the primary key in another table. |
| What is a non-relational database | A database that stores data in formats other than tables, such as documents or key-value pairs. |
| What is a normalized database | A database structured to reduce redundancy and improve data integrity. |
| What is a primary key in a database | A unique identifier for a record in a table. |
| What is a stored procedure in SQL | A set of SQL statements stored in the database to perform a specific task. |
| What is ACID compliance in databases | Ensures Atomicity, Consistency, Isolation, and Durability for transactions. |
| What is database denormalization | Adding redundancy to a database for performance improvement. |
| What is the difference between INNER JOIN and OUTER JOIN | INNER JOIN retrieves matching rows from both tables; OUTER JOIN retrieves matching rows plus non-matching rows from one or both tables. |
| What is the difference between OLTP and OLAP | OLTP handles transaction-focused tasks; OLAP is used for analytics and complex queries. |
| What is the difference between structured data and unstructured data | Structured data is organized in tables; unstructured data lacks a pre-defined format. |
| What is the purpose of a transaction in a database | Ensures that a sequence of operations is completed entirely or not at all. |
| What is the purpose of an index in a database | To speed up the retrieval of data. |
| What is the purpose of database schemas | Define the structure and rules of data storage within a database. |
Front
What does the SQL GROUP BY clause do
Click the card to flip
Back
Aggregates data based on specified columns.
Front
What is the purpose of an index in a database
Back
To speed up the retrieval of data.
Front
What does SQL DISTINCT keyword do
Back
Removes duplicate values in the result set.
Front
What does the SQL clause WHERE do
Back
Filters records based on a specified condition.
Front
What is a stored procedure in SQL
Back
A set of SQL statements stored in the database to perform a specific task.
Front
What does the SQL command DELETE do
Back
Removes data from a table.
Front
What is the difference between INNER JOIN and OUTER JOIN
Back
INNER JOIN retrieves matching rows from both tables; OUTER JOIN retrieves matching rows plus non-matching rows from one or both tables.
Front
What does SQL stand for
Back
Structured Query Language.
Front
What does the SQL command UPDATE do
Back
Modifies existing data in a table.
Front
What is a primary key in a database
Back
A unique identifier for a record in a table.
Front
What is ACID compliance in databases
Back
Ensures Atomicity, Consistency, Isolation, and Durability for transactions.
Front
What is a data warehouse
Back
A central repository for storing large volumes of business data for analysis.
Front
What is a composite key in a database
Back
A key consisting of two or more columns that uniquely identify a record.
Front
What is the purpose of database schemas
Back
Define the structure and rules of data storage within a database.
Front
What character is typically used to denote wildcards in SQL LIKE queries
Back
%.
Front
What is a foreign key in a database
Back
A field in one table that links to the primary key in another table.
Front
What does the SQL HAVING clause do
Back
Applies conditions to groups created by GROUP BY.
Front
What is a normalized database
Back
A database structured to reduce redundancy and improve data integrity.
Front
What is the difference between structured data and unstructured data
Back
Structured data is organized in tables; unstructured data lacks a pre-defined format.
Front
What is the purpose of a transaction in a database
Back
Ensures that a sequence of operations is completed entirely or not at all.
Front
What is the difference between OLTP and OLAP
Back
OLTP handles transaction-focused tasks; OLAP is used for analytics and complex queries.
Front
What does the SQL command SELECT do
Back
Retrieves data from a table.
Front
What is a non-relational database
Back
A database that stores data in formats other than tables, such as documents or key-value pairs.
Front
What is database denormalization
Back
Adding redundancy to a database for performance improvement.
Front
What does the SQL command INSERT do
Back
Adds new rows to a table.
Front
What are database constraints
Back
Rules enforced on data to ensure accuracy and consistency.
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This deck focuses on database design, data querying using SQL, and understanding relational and non-relational database systems.