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primary cost 成本。

primary cuticula

When a query on the relational views is issued , it is repeatedly rewritten using the rules . this process generates number of navigation plans to compute the query ; the cost of these plans is then estimated based on a simple cost model that takes network accesses as the primary cost parameter . in this way , an efficient execution plan is selected for processing the query 當根據關系視圖發出一個查詢時,它被重復的使用重寫規則來重寫,這個過程產生大量的導航方案來運算查詢。這些方案的代價是根據代價模型來評估的。代價模型是用網絡訪問作為原始的代價參數。

The proposals of bigger temperature difference with lower water flow rate and variable primary water flow rate were introduced to reduce the operation cost or primary cost of chilled water system 摘要詳細分析了大溫差小流量系統方案和一次泵變流量系統方案在空調水系統節能方面的異同。

As the primary cost of security transaction , the floatation of trading commission would change the microstructure of security market 證券交易傭金作為證券市場制度中交易費用最直接的體現,其變動必然帶來證券市場的微觀變化。