get the root parent node using neo4j - neo4j

Question

I've imported a csv file to neo4j and created nodes and relationships for them.
In the above the first two nodes comes under db1 and last four nodes comes under db2.
How to find that last four nodes belongs to db2?
Below is the code and csv file
columnname,tablename,databasename,systemname
abc,1a,db1,Finance
def,1a,db1,Finance
ghi,1a,db1,Finance
klm,1a,db1,Finance
abc,1a,db2,Medical
def,1a,db2,Medical
ghi,1a,db2,Medical
klm,1a,db2,Medical
nop,1a,db2,Medical
qrs,1a,db2,Medical
I've created nodes and relationships for the above csv file in neo4j
This is for getting unique values
CREATE CONSTRAINT ON (c:ColumnName) ASSERT c.ColumnName IS UNIQUE;
CREATE CONSTRAINT ON (c:TableName) ASSERT c.TableName IS UNIQUE;
CREATE CONSTRAINT ON (c:DatabaseName) ASSERT c.DatabaseName IS UNIQUE;
CREATE CONSTRAINT ON (c:SystemName) ASSERT c.SystemName IS UNIQUE;
This is for loading csv file and creating nodes and relationships
LOAD CSV WITH HEADERS FROM "file:///test.csv" AS line
MERGE (ColumnName:ColumnName {ColumnName: line.ColumnName})
MERGE (TableName:TableName {TableName:line.TableName})
MERGE (DatabaseName: DatabaseName {DatabaseName:line.DatabaseName})
MERGE (SystemName: SystemName {SystemName:line.SystemName})
This is creating relationships among the nodes
MERGE (ColumnName)-[:iscolumnof]->(TableName)
MERGE (TableName)-[:istableof]->(DatabaseName)
MERGE (DatabaseName)-[:isdatabaseof ]->(SystemName)
If, i select one node 'nop'and expand i'll get the node(1a) 1a and if i expand 1a i'll get all the
nodes(columns). How to find that 'nop' belongs to 'db2'?

Answer 1

As far as I understand, you have a pattern
(:ColumnName)-[:iscolumnof]->(:TableName)-[:istableof]->(:DatabaseName)-[:isdatabaseof ]->(:SystemName)
If you want to test whether a certain :ColumnName belongs to a :DatabaseName
WITH 'nop' AS columnName, 'db2' AS databaseName
MATCH (col:ColumnName {ColumnName:columnName}),(db:DatabaseName
{DatabaseName:databaseName})
RETURN EXISTS((col)-[:iscolumnof]->(:TableName)-[:istableof]->(db)) AS result
If you want all the columns of db2
WITH 'db2' AS databaseName
MATCH (c:ColumnName)-[:iscolumnof]->(:TableName)-[:istableof]->(:DatabaseName {DatabaseName:databaseName})
RETURN c.ColumnName AS column