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Example (cont.)
- Cartesian product: { t | vV ( sS ( lL ( t[vd]=v[d] t[vk]=v[k] t[sk]=s[k] t[sb]=s[b] t[ld]=l[d] t[lb]=l[b] ) ) } (attribute names must be unique)
- Selection: { t | vV ( sS ( lL ( t[vd]=v[d] t[vk]= v[k] t[sk]=s[k] t[sb]=s[b] t[ld]=l[d] t[lb]=l[b] v[k]=s[k] s[b]=l[b] v[d]=l[d] ) ) ) }
- Projection: { t | vV ( sS ( lL ( t[vd]=v[d] v[k]=s[k] s[b]=l[b] v[d]=l[d] ) ) ) }
Notes: