Introduce QueryDsl to unify Entityql and NativeSql APIs

[nakamura-to]

In the previous Criteria API, it was necessary to use two different types of DSL as needed:

• Entityql: A DSL for handling entities, taking into account the identity of each entity.
• NativeSql: A DSL for executing SQL independently of entities. When working with entities, their identity is not considered, and they are treated as simple DTOs.

This pull request introduces a new DSL called QueryDsl. QueryDsl provides users with an intuitive API and determines the need to consider entity identity based on the invoked API.

By using QueryDsl, users no longer have to worry about switching between Entityql and NativeSql.

---

Here is a sample code comparing cases with and without using QueryDsl.

with QueryDsl

// Define only one DSL.
var dsl = new QueryDsl(config);

var e = new Employee_();
var d = new Department_();

var employees = dsl.from(e)
    .leftJoin(d, on -> on.eq(e.departmentId, d.departmentId))
    .associate(e, d, Employee::setDepartment)
    .fetch();

for (var employee : employees) {
    if (employee.getDepartment() == null) {
        dsl.delete(e).single(employee).execute();
    } else {
        // We can use QueryDsl to update a specific column
        dsl.update(e).set(c -> c.value(e.salary, employee.getSalary().add(1000))).execute();
    }
}

without QueryDsl

// Define two DSLs.
var entityql = new Entityql(config);
var nativeSql = new NativeSql(config);

var e = new Employee_();
var d = new Department_();

var employees = entityql.from(e)
    .leftJoin(d, on -> on.eq(e.departmentId, d.departmentId))
    .associate(e, d, Employee::setDepartment)
    .fetch();

for (var employee : employees) {
    if (employee.getDepartment() == null) {
        entityql.delete(e, employee).execute();
    } else {
        // We must use NaitveSql to update a specific column
        nativeSql.update(e).set(c -> c.value(e.salary, employee.getSalary().add(1000))).execute();
    }
}

[momosetkn]

I found typo.

x: KUnifiedInsertStating
o: KUnifiedInsertStarting

The following class is the same.

org.seasar.doma.kotlin.jdbc.criteria.statement.KUnifiedDeleteStating
org.seasar.doma.kotlin.jdbc.criteria.statement.KUnifiedInsertStating
org.seasar.doma.kotlin.jdbc.criteria.statement.KUnifiedSelectStating
org.seasar.doma.kotlin.jdbc.criteria.statement.KUnifiedUpdateStating

[nakamura-to]

Good catch! Thanks!

[momosetkn]

It good to consistency with the single and batch methods. 👍
Previously, Require set to DeleteCofig { allowEmptyWhere = true }.

[momosetkn]

I want to use this method by client-code.
Because I want to prevent the class of the receiver for the associate method changes between the first and subsequent calls.

val query = queryDsl.from(a)
    .leftJoin(b) {
        eq(a.id, b.aId)
    }
val associatedQuery = query
    .associate( /* omission */ ) // receiver class is UnifiedSelectStarting
    .associate( /* omission */ ) // receiver class is UnifiedSelectTerminal
    .associate( /* omission */ ) // receiver class is UnifiedSelectTerminal

I accept automatically change to UnifiedSelectTerminal, when call UnifiedSelectStarting#associate method. but, I want manually change receiver.

When decomposed query into a separate method, it would require double implementation through overloading like bellow code.

fun findList1() {
    val query = queryDsl.from(a)
        .leftJoin(b) {
            eq(a.id, b.aId)
        }
        .associateTableB() // use first associateTableB method
}

fun findList2() {
    val query = queryDsl.from(a)
        .leftJoin(b) {
            eq(a.id, b.aId)
        }
        .associateTableA()
        .associateTableB() // use second associateTableB method
}

fun UnifiedSelectStarting<TableA>.associateTableA(): UnifiedSelectTerminal<TableA> {
    return this.associate( /* omission */ )
}
// overload
fun UnifiedSelectTerminal<TableA>.associateTableA(): UnifiedSelectTerminal<TableA> {
    return this.associate( /* omission */ )
}

fun UnifiedSelectStarting<TableB>.associateTableB(): UnifiedSelectTerminal<TableB> {
    return this.associate( /* omission */ )
}
// overload
fun UnifiedSelectTerminal<TableB>.associateTableB(): UnifiedSelectTerminal<TableB> {
    return this.associate( /* omission */ )
}

[nakamura-to]

In commit 40107f4, we introduced the EntityQueryable and KEntityQueryable interfaces to abstract the common elements of UnifiedSelectStarting and UnifiedSelectTerminal. Do these changes help resolve the issues mentioned above?

[momosetkn]

This abstract receiver class for consistent logic. that is helpful.
thank you.

[momosetkn]

Good that the separation of queries and concerns. 👍
Previously, put code everything EntityqlSelectStarting.