Explain the need for each of the actions in Figure 6-29(a). Parent Required Action on Parent Action

Explain the need for each of the actions in Figure 6-29(a).

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Parent Required Action on Parent Action on Child Insert None. Get a parent. Prohibit. Change children's foreign Modify key or foreign key OK, if new foreign key value matches key values to match new value (cascade update). existing parent. Prohibit. Prohibit. Delete Delete children None. (cascade delete). Prohibit. Figure 6-29(a) – Actions When Parent Is Required