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POImplementing User Defined Fields
 

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    <p>I am creating a laboratory database which analyzes a variety of samples from a variety of locations. Some locations want their own reference number (or other attributes) kept with the sample.</p> <p>How should I represent the columns which only apply to a subset of my samples?</p> <p><strong>Option 1:</strong> Create a separate table for each unique set of attributes?<br/> <code>SAMPLE_BOILER: sample_id (FK), tank_number, boiler_temp, lot_number</code><br/> <code>SAMPLE_ACID: sample_id (FK), vial_number</code><br/> This option seems too tedious, especially as the system grows.<br/></p> <blockquote> <p><strong>Option 1a:</strong> Class table inheritance (<a href="http://martinfowler.com/eaaCatalog/classTableInheritance.html" rel="nofollow noreferrer">link</a>): Tree with common fields in internal node/table<br/> <strong>Option 1b:</strong> Concrete table inheritance (<a href="http://martinfowler.com/eaaCatalog/concreteTableInheritance.html" rel="nofollow noreferrer">link</a>): Tree with common fields in leaf node/table</p> </blockquote> <p><strong>Option 2:</strong> Put every attribute which applies to any sample into the <code>SAMPLE</code> table.<br/> Most columns of each entry would most likely be NULL, however all of the fields are stored together.</p> <p><strong>Option 3:</strong> Create <code>_VALUE_</code> tables for each Oracle data type used. <br/> This option is far more complex. Getting all of the attributes for a sample requires accessing all of the tables below. However, the system can expand dynamically without separate tables for each new sample type.</p> <pre><code>SAMPLE: sample_id* sample_template_id (FK) SAMPLE_TEMPLATE: sample_template_id* version * status date_created name SAMPLE_ATTR_OF sample_template_id* (FK) sample_attribute_id* (FK) SAMPLE_ATTRIBUTE: sample_attribute_id* name description SAMPLE_NUMBER: sample_id* (FK) sample_attribute_id (FK) value SAMPLE_DATE: sample_id* (FK) sample_attribute_id (FK) value </code></pre> <p><strong>Option 4:</strong> (Add your own option)</p>
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    1. COPlease comment on trade-offs between Options 1a and 1b. Also, please offer ideas when using either option on how to handle adding/removing of attributes as the situation arises.
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    2. COAlso, any thoughts concerning the use of the built-in object-relation features in Oracle as a solution?
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    3. COWhile I do not consider this question answered completely, DanVinton gave me the most to think about. This question is actually a subset of the entire model which I am designing.
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