Relation Filtering

Enterprise features a unique relationship loading system that completely eliminates N+1 query patterns. It joins relation tables and filters them in a single query.

Usage

When retrieving a parent record, you can filter which child records are eagerly loaded by passing callback functions to the With[RelationName] or With[RelationName]List method.

account := models.NewAccount(ctx, db)
account.Where(account.IsIDEqual(accountID))

// Load related Deneme, but only if it is active
account.WithDeneme(func(d *models.Deneme) {
    d.Where(d.IsActiveEqual(true))
})

err = account.Get()
if err == nil {
    if account.Deneme != nil {
        fmt.Println("Loaded active deneme:", account.Deneme.GetID())
    } else {
        fmt.Println("No active deneme linked to this account")
    }
}

Similarly, you can load and filter related lists:

deneme := models.NewDeneme(ctx, db)
deneme.Where(deneme.IsIDEqual(denemeID))

// Eagerly load only the related accounts that have the surname "Smith"
deneme.WithAccountList(func(al *models.AccountList) {
    al.Where(al.IsSurnameEqual("Smith"))
})

err = deneme.Get()
if err == nil {
    // Access loaded slice of children
    for _, acc := range deneme.AccountList.Items {
        fmt.Println("Related Smith Account:", acc.GetName())
    }
}

How It Works

When a relation loader is added, Enterprise: 1. Generates an SQL JOIN block (e.g. LEFT JOIN or similar depending on the join layout). 2. appends the custom where clauses defined in the callback directly to the main query’s WHERE list. 3. Automatically maps and scans all retrieved fields into the nested child structs.