The rule for the reconstruction of a relation after it has been decomposed into fragments $($R$1,$ R$2,...,$ Rn$)$ typically involves the natural join $()$ operator. The reconstruction rule is expressed as follows:$\backslash [$ R $=$ R$1\backslash$bowtie R$2\backslash$bowtie $\backslash$ldots $\backslash$bowtie Rn $\backslash ]$This implies that the original relation $\backslash ($ R $\backslash )$ can be reconstructed by performing natural joins $(\backslash (\backslash$bowtie$\backslash ))$ between the decomposed fragments $\backslash ($ R$1,$ R$2,...,$ Rn $\backslash )$ based on common attributes. The natural join ensures that only matching tuples from the decomposed relations are combined, preserving the relationships within the original relation.