Changes between Version 17 and Version 18 of LEGACY - i2b2OntologyCRC-1


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Timestamp:
02/21/11 15:39:12 (13 years ago)
Author:
jeff.lusted
Comment:

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  • LEGACY - i2b2OntologyCRC-1

    v17 v18  
    44=== Note about missing values ===
    55Just a point to be aware of...[[br]]
    6 There seems to be a convention within i2b2 that missing values can be denoted by the @ sign '''''as a value'''''. That is, NULL is not the only way to show missing values. The @ sign can obviously thereby be used where columns are defined as NOT NULL, including primary key columns. I'm not certain whether the choice of @ sign is configurable or not, and where and when they cannot be used.
     6There seems to be a convention within i2b2 that missing values can be denoted by the @ sign '''''as a value'''''. That is, NULL is not the only way to show missing values. The @ sign can obviously thereby be used where columns are defined as NOT NULL, including primary key columns. I'm not certain whether the choice of @ sign is configurable or not, and where and when it cannot be used.
    77
    88=== Ontology Cell tables compared to CRC concept_dimension table ===