Repository builder

A repository is assembled through the fluent gerpo.New[T](). The chain DB → Table → Columns → Build is mandatory. Everything else is optional With* steps between Columns and Build.

Minimal repository

repo, err := gerpo.New[User]().
    Adapter(adapter).
    Table("users").
    Columns(func(m *User, c *gerpo.ColumnBuilder[User]) {
        c.Field(&m.ID).OmitOnUpdate()
        c.Field(&m.Name)
    }).
    Build()

Build() returns gerpo.Repository[User] — a thread-safe object, a single instance serves the whole application.

Full chain of options

repo, err := gerpo.New[User]().
    Adapter(adapter, executor.WithCacheStorage(ctxCache)).      // (1) adapter + executor options
    Table("users").                                         // (2) table name
    Columns(colsFn).                                        // (3) column description
    WithQuery(persistentFn).                                // (4) persistent conditions
    WithSoftDeletion(softFn).                               // (5) DELETE replacement
    WithBeforeInsert(beforeFn).                             // (6) hooks
    WithAfterInsert(afterFn).
    WithBeforeUpdate(beforeUpdFn).
    WithAfterUpdate(afterUpdFn).
    WithAfterSelect(afterSelectFn).
    WithErrorTransformer(mapErr).                           // (7) error mapping
    Build()

1. DB — attach a driver adapter. List of bundled adapters: Adapters. The second argument accepts executor.Option (e.g., WithCacheStorage).
2. Table — physical table name.
3. Columns — mandatory column description. Columns.
4. WithQuery — persistent filters/joins/groupings applied to every request. Persistent queries.
5. WithSoftDeletion — rewrite DELETE as UPDATE. Soft delete.
6. With{Before,After}{Insert,Update}, WithAfterSelect — hooks. Multiple calls stack. Hooks.
7. WithErrorTransformer — run every error through a mapping function. Error transformer.

Methods of the finished repository

type Repository[TModel any] interface {
    GetFirst(ctx context.Context, qFns ...func(m *TModel, h query.GetFirstHelper[TModel])) (*TModel, error)
    GetList(ctx context.Context, qFns ...func(m *TModel, h query.GetListHelper[TModel])) ([]*TModel, error)
    Count(ctx context.Context, qFns ...func(m *TModel, h query.CountHelper[TModel])) (uint64, error)
    Insert(ctx context.Context, model *TModel, qFns ...func(m *TModel, h query.InsertHelper[TModel])) error
    Update(ctx context.Context, model *TModel, qFns ...func(m *TModel, h query.UpdateHelper[TModel])) (int64, error)
    Delete(ctx context.Context, qFns ...func(m *TModel, h query.DeleteHelper[TModel])) (int64, error)
    Tx(tx executor.Tx) Repository[TModel]
    GetColumns() types.ColumnsStorage
}

Every method is described in CRUD operations.

Thread safety

A repository is safe to share across goroutines. Internally, statement objects are reused through sync.Pool, but each call takes its own instance from the pool, so there are no races.

Build errors

Build() returns an error if:

• Adapter or Table is not set;
• Columns contains no columns;
• a virtual column lacks Compute;
• WithSoftDeletion references a field that is not declared as a column.