A relational database can protect the integrity and validity of your data in a number of ways through the application of constraints. In this video, Adam introduces the UNIQUE constraint, and discusses how data validation decisions are driven by the business rules of the organization.
- [Instructor] A relational database … can protect the integrity and validity … of your data in a number of ways. … For the most part, this requires … that you set specific rules on the data tables … to control what will be allowed in. … If someone tries to enter data … that violates one of the rules, … then the database management system … won't allow the record to be saved into the table. … The user will receive an error message … and will have to try again with different values. … In this way, you can be assured that every record … that is saved into the database … meets all of your requirements. … One of the constraints that we can set on a table … is that a column only allow unique values. … In other words, each value in a specific column … will only appear once. … Now, you might be thinking that this sounds … a lot like a primary key. … And you'd be correct. … A primary key is also a unique constraint … placed on the data table. … But where a primary key … is literally the primary way …
Author
Adam Wilbert
Released
9/23/2019- The basics of data storage
- Choosing an entity-relationship design tool
- Using primary keys to identify records
- What to consider when naming objects
- Creating a unique constraint
- Establishing table indexes
- Relating tables with foreign keys
- One-to-many and one-to-one relationships
- Normalization
- Writing SELECT queries in SQL
Skill Level Intermediate
Duration
Views
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Introduction
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1. Get to Know Relational Databases
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What the CRUD?3m 48s
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2. Entity Relationship Diagrams
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Choose an ER design tool5m 7s
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Design a table3m 39s
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3. Data Integrity and Validation
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Data constraints1m 44s
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Create a unique constraint5m 46s
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Define a default value3m 58s
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Establish table indexes4m 49s
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Add check constraints5m 31s
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4. Relationships
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Diagram a relationship2m 42s
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One-to-many relationships2m 10s
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One-to-one relationships1m 10s
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Many-to-many relationships2m 21s
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Self joins2m 17s
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Cascade changes2m 17s
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5. Normalization
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When not to normalize2m 29s
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6. Structured Query Language
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Data definition queries6m 22s
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Data manipulation queries4m 52s
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Create a database view2m 44s
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7. Beyond the Relational Model
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Graph databases1m 38s
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Document databases1m 32s
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Conclusion
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Next steps59s
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Video: Data constraints