Help Needed To Establish Foreign Key Relationship

Hi i have two tables

X and Y

X is the Parent table and Y is the child

X has gpikey char(14) and Record type char(1) as Primary key

y has Name as primary key and column xgpi char(14) which should be the foreignkey to table X

what approach should i take to establish relationship between these two tables.

gpikey of recordtype 5 is equal to value in xgpi in table y

ex: data
Table X
gpikey recordtype

123 1
2345 2
272626 5

Table Y
Name XGPI
dhdhd 272626

x and y are having one to many relationships