Drop Operation

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Definition: Drop Operation

A Drop Operation OpDrop is an Update Operation in which one or more slots (a named slot irii, the default slot, all named slots or all slots) and their corresponding graphs are removed from the Graph Store. There are different variants of the Drop Operation, OpDrop for dropping a named graph, OpDropdef for dropping the default graph (which is equivalent to OpCleardef, since the default graph cannot be removed, but dropping it means only to clear it), OpDropnamed for dropping all named graphs, and OpDropall for dropping all graphs including the default graph.

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

OpDrop(GS, iri) = GS if iri not in graphNames(GS); otherwise, OpDrop(GS, irij) = {DG} union {(irii, Gi ) | i ≠ j and 1 ≤ i ≤ n} where iri = irij

OpDropdef(GS) = OpCleardef(GS)

OpDropnamed(GS) = {DG}

OpDropall(GS) = {{}}

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Graph Management Operations

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Create Operation

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Definition: Create\nOperation

A Create Operation OpCreate is an Update Operation in which (1) a new named slot and (2) a new graph G are created in the Graph Store. The new graph is held in the new slot, and is empty. Other slots and graphs are not affected.

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

OpCreate(GS, iri) = GS union {(iri, {})} if iri not in graphNames(GS); otherwise, OpCreate(GS, iri) = GS

Note:

Since Graph Stores may remove graphs that are left empty, for such Graph Stores any Create Operation performed on an empty or non-existent graph may be viewed as implicitly immediately followed by a

Drop Operation (see next subsection), or simply as an operation with no effect.

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