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RAD Studio (Common)
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Unique Constraint
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RAD Studio (Common)
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Use this dialog box to select the dataset columns you want included in your constraint, which means these columns will be forced to contain only unique values. You can also set one or more columns as your primary key.
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Description |
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Name |
Specifies the name of the constraint. |
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Columns |
Check each column you want included in the constraint. If you indicate a nonunique column as unique, you may generate a runtime errror. |
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Primary key |
Selecting this option sets the checked columns in your constraint as the primary key for the current DataTable. If you set a combination of columns, some of which contain duplicates or null values, you may receive a design-time error and a runtime error. However, if you receive a design-time error, the constraint may still be defined as you indicated, even if it is incorrect. |
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