How hierarchy transformations map to SQL - covering SQLite and SAP HANA 2 #3
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chrisspre
reviewed
Jul 1, 2020
| where Superordinate is null | ||
| union | ||
| select parent_of.node, | ||
| path || '.' || substr('000' || cast(SiblingIdx as string),-4) -- build lexicographical sequence for each node |
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I suggest to refactor and do the conversion from rowId to a four digit number with leading zeros in the parent_of tab table expression.
That way
a) the expression here becomes simpler
b) if the number of digits has to be increased the change is in one place (in contrast to here and in the base case of the recursive CTE)
| salesorg_w_sibling(ID,Superordinate,Name,SiblingIdx) as (select *,rowid from SalesOrganization), | ||
| parent_of(node,parent_node) as (select id, Superordinate from salesorg_w_sibling), | ||
| dfs_traversal_of(node, path) as ( | ||
| select id, '0001' from salesorg_w_sibling -- start with root node |
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This assumes that there is only one root node and that that node is getting the rowId 1.
Might be better to use the SiblingIdx column from salesorg_w_sibling instead of the hardcoded '0001'
(see also comment below about moving the conversing to four digits into salesorg_w_sibling
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