SQLQueryEncoder

struct SQLQueryEncoder

Overview

At present, there is no “input”-capable equivalent of an SQLRow, so this encoder returns a somewhat awkward array of “column name”/“value expression” pairs.

This type is, somewhat confusingly, designed primarily for use with methods such as

• SQLInsertBuilder:

  • model(_:prefix:keyEncodingStrategy:nilEncodingStrategy:userInfo:)

  • model(_:with:)

  • models(_:prefix:keyEncodingStrategy:nilEncodingStrategy:userInfo:)

  • models(_:with:)

• SQLColumnUpdateBuilder:

  • set(model:prefix:keyEncodingStrategy:nilEncodingStrategy:userInfo:)

  • set(model:with:)

• SQLConflictUpdateBuilder:

  • set(excludedContentOf:prefix:keyEncodingStrategy:nilEncodingStrategy:userInfo:)

  • set(excludedContentOf:with:)

It can also be manually invoked. For example:

struct MySimpleUserModel: Codable {
    var id: Int? = nil
    var username: String
    var passwordHash: [UInt8]
    var email: String?
    var createdAt: Date
}

let users: [MySimpleUserModel] = [
    .init(username: "johndoe", passwordHash: (0..<32).random(in: .min ... .max), email: "foo@bar.com", createdAt: .init()),
    .init(username: "janedoe", passwordHash: (0..<32).random(in: .min ... .max), email: nil, createdAt: .init()),
]

// Direct usage (not recommended):
let encoder = SQLQueryEncoder(keyEncodingStrategy: .convertToSnakeCase, nilEncodingStrategy: .asNil)
let rows = try users.map { user in try encoder.encode(user) }
let query = sqlDatabase
    .insert(into: "my_simple_users")
    .columns(rows[0].map(\.0))
for row in rows {
    query.values(row.map(\.1))
}
try await query.run()

// Invoked via SQLInsertBuilder and SQLConflictUpdateBuilder:
let encoder = SQLQueryEncoder(keyEncodingStrategy: .convertToSnakeCase, nilEncodingStrategy: .asNil)
try await sqlDatabase.insert(into: "my_simple_users")
    .models(users, with: encoder)
    .onConflict { $0.set(excludedContentOf: users[0], with: encoder) }
    .run()

// Invoked via SQLUpdateBuilder:
try await sqlDatabase.update("my_simple_users")
    .set(model: users[0], keyEncodingStrategy: .convertToSnakeCase, nilEncodingStrategy: .asNil)
    .where("id", .equal, SQLBind(1))
    .run()