[
https://issues.apache.org/jira/browse/GROOVY-9159?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Daniel Sun updated GROOVY-9159:
-------------------------------
Description:
h2. Background
In order to make querying different types of data sources convenient, we need a
single standard querying interface, i.e. GINQ
h2. Solution
GINQ will reuse most of standard SQL syntax, which can make the learning curve
smooth and avoid infringing the patent of Microsoft.
The basic rationale can be shown as follows:
*User* ==_writes GINQ code_==> *GINQ Engine* ==_translates to Stream-Like
method invocations_==> *Bytecode Writer*
*Note:*
{color:#d04437}1. The exact syntax might be altered before introduction,
currently working on the general principle.{color}
2. All GINQ related keywords are uppercase to avoid breaking existing source
code as possible as we can, e.g. {{FROM}}, {{WHERE}}, {{SELECT}}, etc.
3. In order to support type inference better, {{SELECT}} clause is placed at
the end of GINQ expression.
4. {{alias.VALUE}} is a virtual property and is used to reference the whole
record as value. It can be simplified as {{alias}}.
h2. EBNF
h3. TBD
h2. Examples
h3. 1. Filtering
{code:java}
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
}
def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
age: 10), new Person(name: 'Alice', age: 22)]
def result =
FROM persons p
WHERE p.age > 15 AND p.age <= 35
SELECT p.name
assert ['Daniel', 'Alice'] == result
result =
FROM persons p
WHERE p.age > 15 AND p.age <= 35
SELECT p.VALUE
assert [new Person(name: 'Daniel', age: 35), new Person(name: 'Alice', age:
22)] == result
{code}
{code:java}
def numbers = [1, 2, 3]
def result =
FROM numbers t
WHERE t.VALUE <= 2
SELECT t.VALUE
assert [1, 2] == result
{code}
h3. 2. Joining
{code:java}
import static groovy.lang.Tuple.*
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
City city
}
@groovy.transform.EqualsAndHashCode
class City {
String name
}
def persons = [new Person(name: 'Daniel', age: 35, city: new City('Shanghai')),
new Person(name: 'Peter', age: 10, city: new City('Beijing')), new Person(name:
'Alice', age: 22, city: new City('Hangzhou'))]
def cities = [new City('Shanghai'), new City('Beijing'), new City('Guangzhou')]
// inner join
def result =
FROM persons p INNER JOIN cities c
ON p.city.name = c.name
SELECT p.name
assert ['Daniel', 'Peter'] == result
result =
FROM persons p, cities c
WHERE p.city.name = c.name
SELECT p.name
assert ['Daniel', 'Peter'] == result
result =
FROM persons p, cities c
WHERE p.city = c.VALUE
SELECT p.name
assert ['Daniel', 'Peter'] == result
// left outer join
result =
FROM persons p LEFT JOIN cities c // same to LEFT OUTER JOIN
ON p.city.name = c.name
SELECT p.name, c.name
assert [tuple('Daniel', 'Shanghai'), tuple('Peter', 'Beijing'), tuple('Alice',
null)] == result
// right outer join
result =
FROM persons p RIGHT JOIN cities c // same to RIGHT OUTER JOIN
ON p.city.name = c.name
SELECT p.name, c.name
assert [tuple('Daniel', 'Shanghai'), tuple('Peter', 'Beijing'), tuple(null,
'Guangzhou')] == result
{code}
h3. 3. Projection
{code:java}
import static groovy.lang.Tuple.*
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
}
def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
age: 10), new Person(name: 'Alice', age: 22)]
def result =
FROM persons p
SELECT p.name
assert ['Daniel', 'Peter', 'Alice'] == result
result =
FROM persons p
SELECT p.name, p.age
assert [tuple('Daniel', 35), tuple('Peter', 10), tuple('Alice', 22)] == result
result =
FROM persons p
SELECT [name: p.name, age: p.age]
assert [ [name: 'Daniel', age: 35], [name: 'Peter', age: 10], [name: 'Alice',
age: 22] ] == result
result =
FROM persons p
SELECT new Person(name: p.name, age: p.age)
assert persons == result
result =
FROM persons p
SELECT p.VALUE
assert persons == result
result =
FROM persons p
SELECT p
assert persons == result
{code}
h3. 4. Grouping
{code:java}
import static groovy.lang.Tuple.*
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
String gender
}
def persons = [new Person(name: 'Daniel', age: 35, gender: 'Male'), new
Person(name: 'Peter', age: 10, gender: 'Male'), new Person(name: 'Alice', age:
22, gender: 'Female')]
def result =
FROM persons p
GROUP BY p.gender
SELECT p.gender, MAX(p.age)
assert [tuple('Male', 35), tuple('Female', 22)] == result
{code}
h3. 5. Sorting
{code:java}
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
}
def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
age: 10), new Person(name: 'Alice', age: 22)]
def result =
FROM persons p
ORDER BY p.age
SELECT p.name
assert ['Peter', 'Alice', 'Daniel'] == result
result =
FROM persons p
ORDER BY p.age desc
SELECT p.name
assert ['Daniel', 'Alice', 'Peter'] == result
{code}
h3. 6. Pagination
{code:java}
def numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
def result =
FROM numbers n
LIMIT 5 OFFSET 2
SELECT p.VALUE
assert [2, 3, 4, 5, 6] == result
result =
FROM numbers n
LIMIT 5
SELECT p.VALUE
assert [0, 1, 2, 3, 4] == result
{code}
h3. 7. Nested Queries
{code:java}
def numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
def result =
FROM (
FROM numbers n
WHERE n.VALUE <= 5
SELECT n.VALUE
) v
LIMIT 5 OFFSET 2
SELECT v.VALUE
assert [2, 3, 4, 5] == result
{code}
was:
h2. Background
In order to make querying different types of data sources convenient, we need a
single standard querying interface, i.e. GINQ
h2. Solution
GINQ will reuse most of standard SQL syntax, which can make the learning curve
smooth and avoid infringing the patent of Microsoft.
The basic rationale can be shown as follows:
*User* ==_writes GINQ code_==> *GINQ Engine* ==_translates to Stream-Like
method invocations_==> *Bytecode Writer*
Note:
{color:#d04437}1. The exact syntax might be altered before introduction,
currently working on the general principle.{color}
2. All GINQ related keywords are uppercase to avoid breaking existing source
code as possible as we can, e.g. {{FROM}}, {{WHERE}}, {{SELECT}}, etc.
3. In order to support type inference better, {{SELECT}} clause is placed at
the end of GINQ expression.
4. {{alias.VALUE}} is a virtual property and is used to reference the whole
record as value. It can be simplified as {{alias}}.
h2. EBNF
h3. TBD
h2. Examples
h3. 1. Filtering
{code:java}
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
}
def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
age: 10), new Person(name: 'Alice', age: 22)]
def result =
FROM persons p
WHERE p.age > 15 AND p.age <= 35
SELECT p.name
assert ['Daniel', 'Alice'] == result
result =
FROM persons p
WHERE p.age > 15 AND p.age <= 35
SELECT p.VALUE
assert [new Person(name: 'Daniel', age: 35), new Person(name: 'Alice', age:
22)] == result
{code}
{code:java}
def numbers = [1, 2, 3]
def result =
FROM numbers t
WHERE t.VALUE <= 2
SELECT t.VALUE
assert [1, 2] == result
{code}
h3. 2. Joining
{code:java}
import static groovy.lang.Tuple.*
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
City city
}
@groovy.transform.EqualsAndHashCode
class City {
String name
}
def persons = [new Person(name: 'Daniel', age: 35, city: new City('Shanghai')),
new Person(name: 'Peter', age: 10, city: new City('Beijing')), new Person(name:
'Alice', age: 22, city: new City('Hangzhou'))]
def cities = [new City('Shanghai'), new City('Beijing'), new City('Guangzhou')]
// inner join
def result =
FROM persons p INNER JOIN cities c
ON p.city.name = c.name
SELECT p.name
assert ['Daniel', 'Peter'] == result
result =
FROM persons p, cities c
WHERE p.city.name = c.name
SELECT p.name
assert ['Daniel', 'Peter'] == result
result =
FROM persons p, cities c
WHERE p.city = c.VALUE
SELECT p.name
assert ['Daniel', 'Peter'] == result
// left outer join
result =
FROM persons p LEFT JOIN cities c // same to LEFT OUTER JOIN
ON p.city.name = c.name
SELECT p.name, c.name
assert [tuple('Daniel', 'Shanghai'), tuple('Peter', 'Beijing'), tuple('Alice',
null)] == result
// right outer join
result =
FROM persons p RIGHT JOIN cities c // same to RIGHT OUTER JOIN
ON p.city.name = c.name
SELECT p.name, c.name
assert [tuple('Daniel', 'Shanghai'), tuple('Peter', 'Beijing'), tuple(null,
'Guangzhou')] == result
{code}
h3. 3. Projection
{code:java}
import static groovy.lang.Tuple.*
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
}
def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
age: 10), new Person(name: 'Alice', age: 22)]
def result =
FROM persons p
SELECT p.name
assert ['Daniel', 'Peter', 'Alice'] == result
result =
FROM persons p
SELECT p.name, p.age
assert [tuple('Daniel', 35), tuple('Peter', 10), tuple('Alice', 22)] == result
result =
FROM persons p
SELECT [name: p.name, age: p.age]
assert [ [name: 'Daniel', age: 35], [name: 'Peter', age: 10], [name: 'Alice',
age: 22] ] == result
result =
FROM persons p
SELECT new Person(name: p.name, age: p.age)
assert persons == result
result =
FROM persons p
SELECT p.VALUE
assert persons == result
result =
FROM persons p
SELECT p
assert persons == result
{code}
h3. 4. Grouping
{code:java}
import static groovy.lang.Tuple.*
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
String gender
}
def persons = [new Person(name: 'Daniel', age: 35, gender: 'Male'), new
Person(name: 'Peter', age: 10, gender: 'Male'), new Person(name: 'Alice', age:
22, gender: 'Female')]
def result =
FROM persons p
GROUP BY p.gender
SELECT p.gender, MAX(p.age)
assert [tuple('Male', 35), tuple('Female', 22)] == result
{code}
h3. 5. Sorting
{code:java}
@groovy.transform.EqualsAndHashCode
class Person {
String name
int age
}
def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
age: 10), new Person(name: 'Alice', age: 22)]
def result =
FROM persons p
ORDER BY p.age
SELECT p.name
assert ['Peter', 'Alice', 'Daniel'] == result
result =
FROM persons p
ORDER BY p.age desc
SELECT p.name
assert ['Daniel', 'Alice', 'Peter'] == result
{code}
h3. 6. Pagination
{code:java}
def numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
def result =
FROM numbers n
LIMIT 5 OFFSET 2
SELECT p.VALUE
assert [2, 3, 4, 5, 6] == result
result =
FROM numbers n
LIMIT 5
SELECT p.VALUE
assert [0, 1, 2, 3, 4] == result
{code}
h3. 7. Nested Queries
{code:java}
def numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
def result =
FROM (
FROM numbers n
WHERE n.VALUE <= 5
SELECT n.VALUE
) v
LIMIT 5 OFFSET 2
SELECT v.VALUE
assert [2, 3, 4, 5] == result
{code}
> [GEP] Support LINQ, aka GINQ
> ----------------------------
>
> Key: GROOVY-9159
> URL: https://issues.apache.org/jira/browse/GROOVY-9159
> Project: Groovy
> Issue Type: New Feature
> Reporter: Daniel Sun
> Priority: Major
> Fix For: 4.x
>
>
> h2. Background
> In order to make querying different types of data sources convenient, we need
> a single standard querying interface, i.e. GINQ
> h2. Solution
> GINQ will reuse most of standard SQL syntax, which can make the learning
> curve smooth and avoid infringing the patent of Microsoft.
>
> The basic rationale can be shown as follows:
> *User* ==_writes GINQ code_==> *GINQ Engine* ==_translates to Stream-Like
> method invocations_==> *Bytecode Writer*
> *Note:*
> {color:#d04437}1. The exact syntax might be altered before introduction,
> currently working on the general principle.{color}
> 2. All GINQ related keywords are uppercase to avoid breaking existing source
> code as possible as we can, e.g. {{FROM}}, {{WHERE}}, {{SELECT}}, etc.
> 3. In order to support type inference better, {{SELECT}} clause is placed at
> the end of GINQ expression.
> 4. {{alias.VALUE}} is a virtual property and is used to reference the whole
> record as value. It can be simplified as {{alias}}.
> h2. EBNF
> h3. TBD
> h2. Examples
> h3. 1. Filtering
> {code:java}
> @groovy.transform.EqualsAndHashCode
> class Person {
> String name
> int age
> }
> def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
> age: 10), new Person(name: 'Alice', age: 22)]
> def result =
> FROM persons p
> WHERE p.age > 15 AND p.age <= 35
> SELECT p.name
> assert ['Daniel', 'Alice'] == result
> result =
> FROM persons p
> WHERE p.age > 15 AND p.age <= 35
> SELECT p.VALUE
> assert [new Person(name: 'Daniel', age: 35), new Person(name: 'Alice', age:
> 22)] == result
> {code}
> {code:java}
> def numbers = [1, 2, 3]
> def result =
> FROM numbers t
> WHERE t.VALUE <= 2
> SELECT t.VALUE
> assert [1, 2] == result
> {code}
> h3. 2. Joining
> {code:java}
> import static groovy.lang.Tuple.*
> @groovy.transform.EqualsAndHashCode
> class Person {
> String name
> int age
> City city
> }
> @groovy.transform.EqualsAndHashCode
> class City {
> String name
> }
> def persons = [new Person(name: 'Daniel', age: 35, city: new
> City('Shanghai')), new Person(name: 'Peter', age: 10, city: new
> City('Beijing')), new Person(name: 'Alice', age: 22, city: new
> City('Hangzhou'))]
> def cities = [new City('Shanghai'), new City('Beijing'), new
> City('Guangzhou')]
> // inner join
> def result =
> FROM persons p INNER JOIN cities c
> ON p.city.name = c.name
> SELECT p.name
> assert ['Daniel', 'Peter'] == result
> result =
> FROM persons p, cities c
> WHERE p.city.name = c.name
> SELECT p.name
> assert ['Daniel', 'Peter'] == result
> result =
> FROM persons p, cities c
> WHERE p.city = c.VALUE
> SELECT p.name
> assert ['Daniel', 'Peter'] == result
> // left outer join
> result =
> FROM persons p LEFT JOIN cities c // same to LEFT OUTER JOIN
> ON p.city.name = c.name
> SELECT p.name, c.name
> assert [tuple('Daniel', 'Shanghai'), tuple('Peter', 'Beijing'),
> tuple('Alice', null)] == result
> // right outer join
> result =
> FROM persons p RIGHT JOIN cities c // same to RIGHT OUTER JOIN
> ON p.city.name = c.name
> SELECT p.name, c.name
> assert [tuple('Daniel', 'Shanghai'), tuple('Peter', 'Beijing'), tuple(null,
> 'Guangzhou')] == result
> {code}
> h3. 3. Projection
> {code:java}
> import static groovy.lang.Tuple.*
> @groovy.transform.EqualsAndHashCode
> class Person {
> String name
> int age
> }
> def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
> age: 10), new Person(name: 'Alice', age: 22)]
> def result =
> FROM persons p
> SELECT p.name
> assert ['Daniel', 'Peter', 'Alice'] == result
> result =
> FROM persons p
> SELECT p.name, p.age
> assert [tuple('Daniel', 35), tuple('Peter', 10), tuple('Alice', 22)] == result
> result =
> FROM persons p
> SELECT [name: p.name, age: p.age]
> assert [ [name: 'Daniel', age: 35], [name: 'Peter', age: 10], [name: 'Alice',
> age: 22] ] == result
> result =
> FROM persons p
> SELECT new Person(name: p.name, age: p.age)
> assert persons == result
> result =
> FROM persons p
> SELECT p.VALUE
> assert persons == result
> result =
> FROM persons p
> SELECT p
> assert persons == result
> {code}
> h3. 4. Grouping
> {code:java}
> import static groovy.lang.Tuple.*
> @groovy.transform.EqualsAndHashCode
> class Person {
> String name
> int age
> String gender
> }
> def persons = [new Person(name: 'Daniel', age: 35, gender: 'Male'), new
> Person(name: 'Peter', age: 10, gender: 'Male'), new Person(name: 'Alice',
> age: 22, gender: 'Female')]
> def result =
> FROM persons p
> GROUP BY p.gender
> SELECT p.gender, MAX(p.age)
> assert [tuple('Male', 35), tuple('Female', 22)] == result
> {code}
> h3. 5. Sorting
> {code:java}
> @groovy.transform.EqualsAndHashCode
> class Person {
> String name
> int age
> }
> def persons = [new Person(name: 'Daniel', age: 35), new Person(name: 'Peter',
> age: 10), new Person(name: 'Alice', age: 22)]
> def result =
> FROM persons p
> ORDER BY p.age
> SELECT p.name
> assert ['Peter', 'Alice', 'Daniel'] == result
> result =
> FROM persons p
> ORDER BY p.age desc
> SELECT p.name
> assert ['Daniel', 'Alice', 'Peter'] == result
> {code}
> h3. 6. Pagination
> {code:java}
> def numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
> def result =
> FROM numbers n
> LIMIT 5 OFFSET 2
> SELECT p.VALUE
> assert [2, 3, 4, 5, 6] == result
> result =
> FROM numbers n
> LIMIT 5
> SELECT p.VALUE
> assert [0, 1, 2, 3, 4] == result
> {code}
> h3. 7. Nested Queries
> {code:java}
> def numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
> def result =
> FROM (
> FROM numbers n
> WHERE n.VALUE <= 5
> SELECT n.VALUE
> ) v
> LIMIT 5 OFFSET 2
> SELECT v.VALUE
> assert [2, 3, 4, 5] == result
> {code}
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