Class Four Notes (401)
Data Modeling
nosql vs sql
- Relational database is suitable for the complex query intensive environment, and non-relational database is suitable for hierarchical data storage.
- SQL can be scaled by adding more rows/columns, noSQL can be scaled by adding more properties to expand the key-value pair.
sql modeling techniques
- A “One-to-Many” relationship is when a table can be related to more than one entry in another. They can be related using the primary key and foreign keys
- A primary key generally focuses on the uniqueness of the table. It assures the value in the specific column is unique. A foreign key is generally used to build a relationship between the two tables.
Videos
- Keywords are called using
SELECT, and parameters are called using WHERE
- In normalization, columns are assigned to tables in such a way that each business fact is stored only once, or in other words, a table should not contain duplicate data.
- “One-to-One” is when one record in one table is associated with one record in another table(ex. ID to Customer Name), “One-to-Many” is when one record in a table can relate to more than one entries to another table (ex. one dormatry rented to many students), “Many-to-Many” is multiple records in one table can be associated with multiple records in another table (ex. many customers can purchase many products).
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References