public void Join()
{
using var log = Log();
LevelDB.Options options = new LevelDB.Options();
options.CreateIfMissing = true;
using LevelDB.DB db = new LevelDB.DB(options, $"/tmp/DBTests-Join");
var parents = db.Cast <Parent, string>();
var children = db.Cast <Child, string>();
parents.Put(new Parent(1), "aaa");
parents.Put(new Parent(2), "bbb");
children.Put(new Child(1, 11), "afirst");
children.Put(new Child(1, 12), "asecond");
children.Put(new Child(2, 21), "afirst");
children.Put(new Child(2, 22), "asecond");
{
var join =
from parent
in parents.GetIterable().Range(new Parent(1), new Parent(3))
join child
in children.GetIterable().Range(new Child(1, 1), new Child(3, 1))
on parent.Key.parentId equals child.Key.parentId
select $"[{parent.Value} => {child.Key.parentId}:{child.Key.childId}:{child.Value}]";
Assert.Equal(
"[aaa => 1:11:afirst]; [aaa => 1:12:asecond]; [bbb => 2:21:afirst]; [bbb => 2:22:asecond]",
string.Join("; ", join));
}
{
IEnumerable <KeyValuePair <Tuple <Parent, Child>, Tuple <string, string> > > streamJoin =
parents.GetIterable().Range(new Parent(1), new Parent(3))
.Join(
children.GetIterable().Range(new Child(1, 1), new Child(3, 1)),
(k1, k2) => k1.parentId.CompareTo(k2.parentId));
Assert.Equal(
"1/11 => aaa/afirst; 1/12 => aaa/asecond; 2/21 => bbb/afirst; 2/22 => bbb/asecond",
string.Join("; ", streamJoin.Select(row => $"{row.Key.Item1.parentId}/{row.Key.Item2.childId} => {row.Value.Item1}/{row.Value.Item2}")));
}
{
IMergeJoinIterable <Parent, Child, string, string> streamJoin =
Tuple.Create(
parents.GetIterable().Range(new Parent(1), new Parent(3)),
children.GetIterable().Range(new Child(1, 1), new Child(3, 1)))
.Join2(sizeof(int), sizeof(int));
Assert.Equal(
"1/11 => aaa/afirst; 1/12 => aaa/asecond; 2/21 => bbb/afirst; 2/22 => bbb/asecond",
string.Join("; ", streamJoin.Select(row => $"{row.Key.Left.parentId}/{row.Key.Right.childId} => {row.Value.Left}/{row.Value.Right}")));
}
}
