daScript/tutorials/sql/02-insert_data.das at master · NicSavichev/daScript · GitHub

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options gen2

require daslib/sql

require sqlite/sqlite_boost

// [sql_table] is a structure macro. At compile time it reads the field

// metadata (@sql_primary_key etc.) and generates, attached to type Car:

// - per-type CREATE / DROP / INSERT SQL emitters

// - a row-binder that binds each field to the right ? placeholder

// The user-facing `create_table`, `drop_table_if_exists`, `insert` generics

// in sqlite_boost forward to those helpers.

// Optional `name="Cars"` keeps the on-disk table name explicit when the

// struct name (Car) doesn't match the table name you want (Cars).

[sql_table(name="Cars")]

struct Car {

@sql_primary_key Id : int

Name : string

Price : int

}

[export]

def main() {

// `with_sqlite` panics if the file can't be opened. For user-supplied

// paths the future error-handling chunk introduces a non-panic

// Result<T, string>-returning sibling.

with_sqlite("test.db") $(db) {

db |> drop_table_if_exists(type<Car>)

db |> create_table(type<Car>)

// `check_schema` verifies the open DB's columns match the [sql_table]

// struct on (name, type, NOT NULL, PRIMARY KEY). Recommended startup

// pattern for code that opens a DB it didn't just create — fails loud

// instead of letting a column rename surface as a silent wrong-result

// later. Use `try_check_schema` for the non-panicking Option form

// (returns SqlError = Option<string>: none on match, some(errmsg) on mismatch).

db |> check_schema(type<Car>)

// `insert` is overloaded on Car vs array<Car>. Both overloads are

// generated by [sql_table]; the array form runs inside a single

// BEGIN/COMMIT transaction so 8 rows = 1 fsync, not 8.

// Panics on failure (constraint violation, BUSY, IO).

db |> insert([

Car(Id = 1, Name = "Audi", Price = 52642),

Car(Id = 2, Name = "Mercedes", Price = 57127),

Car(Id = 3, Name = "Skoda", Price = 9000),

Car(Id = 4, Name = "Volvo", Price = 29000),

Car(Id = 5, Name = "Bentley", Price = 350000),

Car(Id = 6, Name = "Citroen", Price = 21000),

Car(Id = 7, Name = "Hummer", Price = 41400),

Car(Id = 8, Name = "Volkswagen", Price = 21600)

])

}

daScript/tutorials/sql/02-insert_data.das at master · NicSavichev/daScript · GitHub

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