Fact таблицы и измерения

Fact/dimension разделение — фундамент dimensional modeling для analytics warehouses.

Fact tables

Measurements: bet_amount, deposit_amount. Foreign keys к dimensions. Additive facts: суммируются. Semi-additive: aggregate только по некоторым dimensions. Non-additive: ratios. Grain: level of detail (per bet, per session, per day). Grain choice critical.

Dimension tables

Contexts: dim_player, dim_game, dim_date. Attributes: descriptive. Hierarchies: geography, time. Surrogate keys обычно (integer identity) для performance. Business keys как attributes. Wide dimensions: 30–100+ columns норма.

SCD (Slowly Changing Dimensions)

Type 1: overwrite (текущее значение). Type 2: history через effective dates (для player attributes). Type 3: current + previous. Type 6: hybrid. Choice depends on business need. Player VIP tier changes — обычно SCD Type 2 для tracking.

Common facts в iGaming

fact_bet: per bet, sat amount, outcome, RTP contribution. fact_deposit: transactions с status. fact_session: per session metrics. fact_bonus_activity: bonus events. Aggregated marts: daily_player_stats, daily_game_stats. Multiple granularities для different queries.