| In the search for a good SQL Server DBA you'll likely | | | | table depending upon data from another table. |
| interview many candidates. While there are many | | | | There are several types of joins: INNER JOINs, |
| things a hiring manager looks for in an interview, for | | | | OUTER JOINs, CROSS JOINs. |
| instance what is termed soft skills definitely plays a | | | | What is normalization? Explain different levels of |
| role, managers are basically looking for someone who | | | | normalization? |
| knows what they are doing. In other words, it's what | | | | The process of applying normal forms sequentially on |
| you know or at the very least appear to know in the | | | | a database design to efficiently organize data. 1NF |
| interview that counts. | | | | Eliminate Repeating Groups - Make a separate table |
| Here are a few questions to review that will better | | | | for each set of related attributes, and give each table |
| prepare you for an interview for a SQL DBA position.. | | | | a primary key. |
| What is SQL? (hopefully this is a given if you are | | | | 2NF Eliminate Redundant Data - If an attribute |
| interviewing for type of position). SQL stands for | | | | depends on only part of a multi-valued key, remove it |
| 'Structured Query Language'. | | | | to a separate table. 3NF Eliminate Columns Not |
| What is SELECT statement? A SELECT statement | | | | Dependent On Key - If attributes do not contribute to |
| allows you to select a set of values from a table in a | | | | a description of the key, remove them to a separate |
| database. The values selected from the database | | | | table. |
| table depend on the various conditions that are | | | | BCNF Boyce-Codd Normal Form - If there are |
| specified in the SQL query. | | | | non-trivial dependencies between candidate key |
| How do you delete a record from a database? Use | | | | attributes, separate them out into distinct tables. |
| the DELETE statement to remove records from a | | | | 4NF Isolate Independent Multiple Relationships - No |
| database. | | | | table may contain two or more 1:n or n:m relationships |
| What's the difference between a primary key and a | | | | that are not directly related. |
| unique key? Both primary key and unique enforce | | | | 5NF Isolate Semantically Related Multiple Relationships |
| uniqueness of the column on which they are defined. | | | | -There may be practical constrains on information that |
| But by default primary key creates a clustered index | | | | justify separating logically related many-to-many |
| on the column, where are unique creates a | | | | relationships. |
| nonclustered index by default. Another major | | | | ONF Optimal Normal Form - a model limited to only |
| difference is that, primary key doesn't allow NULLs, but | | | | simple (elemental) facts, as expressed in Object Role |
| unique key allows one NULL only. | | | | Model notation. |
| What is a join and what are some examples of types | | | | DKNF Domain-Key Normal Form - a model free from |
| of joins? Joins are used in queries to connect different | | | | all modification anomalies. |
| tables together. Joins allow you to select data from a | | | | |