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Database Concepts and SQL (DataSys+ DS0-001) Flashcards
CompTIA DataSys+ DS0-001 Flashcards
| Front | Back |
| What does SQL stand for | Structured Query Language. |
| What does the COUNT function do | Returns the number of rows that match a specified condition. |
| What does the DISTINCT keyword do | Removes duplicate rows from the result set. |
| What does the INSERT statement do | Adds new data or records to a database table. |
| What does the ROLLBACK command do | Undoes all changes made during a transaction. |
| What does the SELECT statement do | Retrieves data from one or more database tables. |
| What does the UNION operator do | Combines the results of two or more SELECT statements, removing duplicates by default. |
| What is a composite key | A primary key made up of two or more columns. |
| What is a data type in a database | Defines the kind of data a column can hold, such as INTEGER or VARCHAR. |
| What is a foreign key | A field in one table that uniquely identifies a row in another table. |
| What is a JOIN in SQL | A command to combine rows from two or more tables based on a related column. |
| What is a primary key | A unique identifier for a record in a database table. |
| What is a primary purpose of an index in a database | To speed up search and retrieval operations. |
| What is a relational database | A database structured to recognize relationships among stored items of information. |
| What is a schema in a database | The structure that defines tables, columns, relationships, and other elements. |
| What is a subquery | An embedded query inside another SQL query. |
| What is a transaction in a database | A sequence of operations performed as a single logical unit of work. |
| What is a unique constraint | Ensures all values in a column or a set of columns are different. |
| What is a view in a database | A virtual table based on the result of a SQL query. |
| What is ACID in relation to databases | Stands for Atomicity, Consistency, Isolation, Durability; principles for reliable database transactions. |
| What is the difference between an INNER JOIN and OUTER JOIN | INNER JOIN returns records with matching values in both tables, OUTER JOIN includes matched and unmatched rows. |
| What is the difference between DELETE and TRUNCATE | DELETE removes specific rows and can use a WHERE clause; TRUNCATE removes all rows from a table. |
| What is the purpose of normalization | To reduce data redundancy and improve data integrity. |
| What is the purpose of the GROUP BY clause | Organizes data into groups based on specified columns. |
| What is the purpose of the WHERE clause | Filters the result set to include only rows that meet certain conditions. |
| What is the role of the HAVING clause | Filters groups after the GROUP BY operation. |
This deck focuses on databases, including relational database design, SQL queries, and basic database management tasks.