Clear Operation

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Definition: Clear Operation

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A Clear Operation OpClear is an Update Operation in which triples are deleted from the Graph Store, either from a named slot, the default slot, all named slots or all slots. There are different variants of the Clear Operation, OpClear for clearing a named graph, OpCleardef for clearing the default graph, OpClearnamed for clearing all named graphs, and OpClearall for clearing all graphs including the default graph.

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Let GS = {DG} union {(irii, Gi) | 1 ≤ i ≤ n} and graphNames(GS) = { irii | 1 ≤ i ≤ n}, then

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OpClear(GS, iri) = GS if iri not in graphNames(GS); otherwise, OpClear(GS, irij) = ( GS minus {(irij, Gj)} ) union {(irij,{})}, where (irij, Gj) ∈ GS and iri = irij

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OpCleardef(GS) = {{}} union {(irii, Gi) | 1 ≤ i ≤ n}

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OpClearnamed(GS) = {DG} union {(irii, {}) | 1 ≤ i ≤ n}

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OpClearall(GS) = {{}} union {(irii, {}) | 1 ≤ i ≤ n}

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Note:

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Since Graph Stores may remove graphs that are left empty, for such Graph Stores any Clear Operation performed on a named graph may be viewed as immediately followed by a

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Drop Operation, see below.