Reference Tables

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Reference Tables

A reference table is a table that contains a list of reference values. A reference table is designated by the prefix RT_, as in RT_ANALYTE.


Reference values, also known as lookup lists or valid values, are the information found in reference tables. They include such things as analytes, matrices, and units. Reference values are found in many places in EQuIS as pull-down or drop-down lists. Requiring selection from a list (rather than open text entry) ensures consistency in spelling, which ensures consistency in data.


Analyte (RT_ANALYTE)

Matrix (RT_MATRIX)

Unit (RT_UNIT)





Soil Quality Control




Parts Per Million


Water Quality Control

Parts Per Billion

Vinyl Chloride

Pounds Per Cubic Foot

Carbon Disulfide



Meters Per Day


Degrees Celsius


The analyte reference table, RT_ANALYTE, provides a list of valid analytes. The RT_MATRIX table lists matrices or media from which a sample can be derived. In both cases, the values contained in these tables help describe something about a project (i.e. contaminant is benzene, and sample was taken from soil). However, benzene and soil, by themselves, are not respective to any particular project as a sample ID would be. Similarly, the unit reference table contains a list of valid units such as feet and milligrams/liter or mg/L. These descriptors can be used in any project.


While reference tables serve to control vocabulary and enforce consistency, they can be modified. As an organization, particular values can be selected. For example, when dealing with analytical methods, "EPA8060", "EPA 8060" or just "8060" can be used. All of these are valid representations of a particular method; however, data should be submitted using only one of these terms. If some of the data uses "8060" and the rest of the data uses "EPA8060", then reports based on a single method would be incomplete.


One of the first steps in implementing EQuIS is establishing the desired lists of reference values. Selecting reference values helps to ensure consistency and reliability in the database and also in reporting.


Reference tables can contain other information besides just a value, information that describes the particular value. For example, in RT_ANALYTE, you may have a CAS number (CAS_RN), analyte type or analyte short name in addition to the analyte name.


Custom tables prefixed with rt_ (or RT_) will appear in the Reference tables.