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Relational theory <br />? <br /> <br />Database design and administration <br />? <br /> <br />Standard Query Language (SQL) <br />? <br /> <br />INFORMIX DB tools (DB-Access, ISQL) <br />? <br /> <br />CRDSS database structure, entity relationship diagram (ERD), underlying relationships <br />? <br />derived from the ERD and schema <br /> <br />Water resources data <br />? <br />In addition, use of the INFORMIX toolkit requires supervision by an individual with a higher <br />database skill level and an understanding of the data involved in the refresh process. <br />The dynamic flexibility of the relational database structure allows the skilled database administrator <br />to create temporary work tables in areas physically isolated from the production data, but still <br />positioned to allow controlled testing and querying against the rules and requirements present within <br />the production environment. Temporary working tables can be added and dropped whenever <br />necessary without impacting end-user productivity. External ASCII-delimited data files can be <br />imported into these work tables using SQL. Once contained within the database, incoming data can <br />be viewed, modified, tested and reported on using the built-in capabilities of the INFORMIX <br />product. <br />Example: <br /> An existing referential integrity rule is that while a station can exist in the <br />database without any streamflow data, streamflow data cannot exist in the database for a <br />station that does not currently exist in the database. The station must be added first. If the <br />streamflow data were permitted into the database, there would be no way for application <br />software to ever report on it because raw data are never retrieved directly, but only <br />through the relationships that have been defined in the database (i.e., streamflow data is <br />retrieved for a station, not independently). <br />To enforce this rule, incoming streamflow data would be interrogated by a simple SQL <br />query to make sure that the station in each streamflow record already exists in the <br />database. <br />select i.station_id <br /> from inputStreamFlowData i <br /> where not exists <br /> (select * from station <br /> where s.station_id = i.station_id) <br />A report would be generated of any input records having stations that do not currently <br />exist in the database. SQL scripts that are developed and used during the validation <br />process can be saved to disk for re-use in the future. <br />2 <br />a320/taskmems/ 2-13-01.doc 01/03/97 <br />