By not applying key constraints in the database, a field that requires information has been left empty.

由于没有在数据库中应用键约束，必须包含信息的字段却是空的。

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Four interactive instructional movies were created for Lotus Forms Designer; three demonstrate various computes in the compute Editor, and one shows how to set constraints on a field.

为Lotus Forms Designer创建了4个交互式的演示视频；其中3个演示Compute Editor中的各种计算，另一个演示如何在字段上设置约束。

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Repeat the previous steps to set constraints for the Supplier ID input field.

重复前面的步骤为 Supplier ID 输入字段设置约束。

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As a result of the variety of actors represented (political decision makers, site managers, museum directors, local community representatives, the World Tourism Organization, the private sector, etc.), the seminar resulted in the creation of a detailed inventory of field experiences, shared best practices and identified constraints and challenges to tourism memory.

UNESCO: CULTURE

Swansea-born former Wales striker Hartson says financial constraints could turn those dreams into a nightmare on the field.

BBC: Hartson warns Cardiff and Swansea over Premier dream

Clusters are good in any field because they boost productivity and innovation, and cluster policy seeks to reduce constraints and encourage externalities to raise the productivity of competition.

ECONOMIST: The West Lothian question