1. TreSQL (Tree SQL)
Mārtiņš Rumovskis

2. Agenda
 Motivation
 TreSQL vs SQL
 TreSQL statement structure
 Scala API

3. Agenda
 Motivation
 TreSQL vs SQL
 TreSQL statement structure
 Scala API

4. Old Good SQL
 Traditionally we can get data in the tabular form
DEPTNO DNAME LOC
30 SALES Chicago

5. Old Good SQL
 Traditionally we can get data in the tabular form
DEPTNO DNAME LOC
30 SALES Chicago
 But we need something like this...
DEPTNO DNAME LOC EMPNO ENAME
30 SALES Chicago 1 ALLEN
2 WARD
3 MARTIN
20 RESEARCH Dallas 4 MILLER
5 SCOTT

6. Old Good SQL
 Traditionally we can get data in the tabular form
DEPTNO DNAME LOC
30 SALES Chicago
 But we need somethink like this...
DEPTNO DNAME LOC EMPNO ENAME
30 SALES Chicago 1 ALLEN
2 WARD
3 MARTIN
20 RESEARCH Dallas 4 MILLER
5 SCOTT
 Or like this...
NAME DRIVER_LIC LANGUAGES
SCOTT A,B EN,LV,RU
MILLER B,C EN,IT

7. Old Good SQL (Cont)
 We need to write joins
select * from emp e join dept d on e.deptno = d.deptno

8. Old Good SQL (Cont)
 We need to write joins
select * from emp e join dept d on e.deptno = d.deptno
 Explicitly specify id column name
select * from dept where id in (10, 20, 30)

9. Problems of JDBC
 JDBC
 We need to do SQL to Java mappings
setXXX(idx, value)
...well you know
 We need to bind every variable in the SQL statement noted as
‘?’ otherwise exception occurs

10. Problems of JDBC
 JDBC
 We need to do SQL to Java mappings
setXXX(idx, value)
...well you know
 We cannot run several queries
select * from dept where deptno = 10,
select * from emp where job = 'MGR'

11. What’s about ORM?
 ORM (Hibernate)
 We need to define class model and mapping

12. What’s about ORM?
 ORM (Hibernate)
 We need to define class model and mapping
 And we still need SQL (for advanced use) 

13. Agenda
 Motivation
 TreSQL vs SQL
 TreSQL statement structure
 Scala API

14. Sql vs TreSQL
 Simple SQL
SQL: select * from dept

15. Sql vs TreSQL
 Simple SQL
SQL: select * from dept
TreSQL: dept

16. Sql vs TreSQL
 Select... Where
SQL: select * from dept where deptno = 10

17. Sql vs TreSQL
 Select... Where
SQL: select * from dept where deptno = 10
TreSQL: dept[10]

18. Sql vs TreSQL
 More complex select
SQL: select deptno, dname from dept
select ename from emp where deptno = :deptno

19. Sql vs TreSQL
 More complex select (needs programming when using
SQL)
SQL: select deptno, dname from dept
select ename from emp where deptno = :deptno
TreSQL: dept{deptno, dname,
|emp[:1(1) = deptno] {ename} employees}

20. Sql vs TreSQL
 Multiple selects
SQL: select * from dept where deptno = 10
select * from emp where job = 'MGR'

21. Sql vs TreSQL
 Multiple selects
SQL: select * from dept where deptno = 10
select * from emp where job = 'MGR‘
TreSQL: dept[10], emp[job = 'MGR']

22. Sql vs TreSQL
 Outer join order by
SQL: select * from dept
left join emp on dept.deptno = emp.deptno
order by dname

23. Sql vs TreSQL
 Outer join order by
SQL: select * from dept
left join emp on dept.deptno = emp.deptno
order by dname
TreSQL: dept/emp? #(dname)

24. Sql vs TreSQL
 In, subselect
SQL: select * from dept where deptno
in (select deptno from emp)

25. Sql vs TreSQL
 In, subselect
SQL: select * from dept where deptno
in (select deptno from emp)
TreSQL: dept [deptno in (emp{deptno})]

26. Sql vs TreSQL
 Exists, correlated subselect
SQL: select * from dept d where
exists select * from emp e
where d.deptno = e.deptno

27. Sql vs TreSQL
 Exists, correlated subselect
SQL: select * from dept d where
exists select * from emp e
where d.deptno = e.deptno
TreSQL: dept d[(emp e[e.deptno = d.deptno])]

28. Sql vs TreSQL
 More complex example (using SQL programming is
needed)
dept{deptno, dname,
|emp[sal >= hisal & sal <= losal]salgrade[deptno =
:1(1)]
{grade, hisal, losal, count(empno) empcount,
|emp/dept[sal >= :1(2) & sal <= :1(3) &
emp.deptno = :2(1)]
{ename, emp.deptno, dname, sal}#(empno) emps
} (grade, hisal, losal) #(1) salgrades
} #(deptno)

29. Agenda
 Motivation
 TreSQL vs SQL
 TreSQL statement structure
 Scala API

30. TreSQL Language Structure
 SELECT statement structure
<from>[<where>][<columns>][<group by>
[<having>]][<order>][<offset> [<limit>]]
table1[join cond]table2[where]{columns} (group
cols)^(having expr) #(order) (offset limit)

31. TreSQL Language Structure
 INSERT
DEPT {DEPTNO, DNAME, LOC}
+ [10, "ACCOUNTING", "NEW YORK"]
 Statement structure
table {col1, col2} + [val1, val2]

32. TreSQL Language Structure
 UPDATE
emp[1] {ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO} =
[?, ?, ?, ?, ?, ?, ?]
 Statement structure
table [where] {col1, col2} = [val1, val2]

33. TreSQL Language Structure
 DELETE
emp - [1]
 Statement structure
table - [where]

34. Agenda
 Motivation
 TreSQL vs SQL
 TreSQL statement structure
 Scala API

35. Scala API
 Code example:
import org.tresql._
Env update connection
Query.foreach("dept[?]{dname}", 10) {row=> println(row(0))}
//
val expr = Query.build("emp[deptno = ?]{*}")
val result = expr.select(10)
result foreach println
expr close
Jsonizer.jsonize(Query(expr, pars), writer, rType)

36. Scala API
 Code example:
import org.tresql._ org.tresql.Env
Expression execution environment. Used for setting
database connection.
Env update connection
Query.foreach("dept[?]{dname}", 10) {row=> println(row(0))}
//
val expr = Query.build("emp[deptno = ?]{*}")
val result = expr.select(10)
result foreach println
expr close

37. Scala API
 Code example:
import org.tresql._
Env update connection
Query.foreach("dept[?]{dname}", 10) {row=> println(row(0))}
// org.tresql.Query
Expression execution, result iteration
val expr = Query.build("emp[deptno = ?]{*}")
val result = expr.select(10)
result foreach println
expr close

38. Scala API
 Code example:
import org.tresql._
Env update connection
Query.foreach("dept[?]{dname}", 10) {row=> println(row(0))}
org.tresql.Expr
// Builded expression. Equivalent to java.sql.PreparedStatement
val expr = Query.build("emp[deptno = ?]{*}")
val result = expr.select(10)
result foreach println
expr close

39. Scala API
 Code example:
import org.tresql._
Env update connection
Query.foreach("dept[?]{dname}", 10) {row=> println(row(0))}
//
val expr = Query.build("emp[deptno = ?]{*}")
val result = expr.select(10)
org.tresql.Expr
result foreach println Expression result – org.tresql.Result
expr close

40. Scala API
 Code example:
import org.tresql._
org.tresql.Env update connection
org.tresql.Query.foreach("dept[?]{dname}", 10) {row=> println(row(0))}
//
val expr = Query.build("emp[deptno = ?]{*}")
val result = expr.select(10)
org.tresql.Expr
result foreach println
Result JSON formatting
expr close
Jsonizer.jsonize(Query(expr, pars), writer, rType)

41. Scala API
 Code example:
import org.tresql._
org.tresql.Env update connection
org.tresql.Query.foreach("emp[sal > ? & deptno = ?]", 1000, 10) {row=>
println(row(0))}
org.tresql.Query.foreach("emp[sal > ? & deptno = ?]", 1000) {row=>
println(row(0))}
org.tresql.Expr
Optional binding

42. That’s about it!
Visit: https://github.com/mrumkovskis/Query

43. Q&A