For​

EdgeQL supports a top-level for statement. These “for loops” iterate over each element of some input set, execute some expression with it, and merge the results into a single output set.

1. for number in {0, 1, 2, 3}
2. union (
3. select { number, number + 0.5 }
4. );

1. {0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5}

This statements iterates through each number in the set. Inside the loop, the number variable is bound to a singleton set. The inner expression is executed for every element of the input set, and the results of each execution are merged into a single output set.

The union keyword is a required part of the for statement syntax; it is intended to indicate explicitly that the results of each loop execution are ultimately merged.

Bulk inserts​

The for statement is commonly used for bulk inserts.

1. for hero_name in {'Cersi', 'Ikaris', 'Thena'}
2. union (
3. insert Hero { name := hero_name }
4. );

1. {
2. default::Hero {id: d7d7e0f6-40ae-11ec-87b1-3f06bed494b9},
3. default::Hero {id: d7d7f870-40ae-11ec-87b1-f712a4efc3a5},
4. default::Hero {id: d7d7f8c0-40ae-11ec-87b1-6b8685d56610}
5. }

This statements iterates through each name in the list of names. Inside the loop, hero_name is bound to a str singleton, so it can be assigned to Hero.name.

Instead of literal sets, it’s common to use a json parameter for bulk inserts. This value is then “unpacked” into a set of json elements and used inside the for loop:

1. with
2. raw_data := <json>$data,
3. for item in json_array_unpack(raw_data) union (
4. insert Hero { name := <str>item['name'] }
5. );

1. Parameter <json>$data: [{"name":"Sersi"},{"name":"Ikaris"},{"name":"Thena"}]
2. {
3. default::Hero {id: d7d7e0f6-40ae-11ec-87b1-3f06bed494b9},
4. default::Hero {id: d7d7f870-40ae-11ec-87b1-f712a4efc3a5},
5. default::Hero {id: d7d7f8c0-40ae-11ec-87b1-6b8685d56610}
6. }

A similar approach can be used for bulk updates.

︙