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Home/Questions/SQL/Explain normalization in databases and its importance. Write an SQL query to handle SCD-1 or SCD-3

Explain normalization in databases and its importance. Write an SQL query to handle SCD-1 or SCD-3

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**Architectural Logic**: Normalization ensures integrity; SCD-1/3 handles dimension updates. **Normalization**: 1NF–3NF; reduces redundancy; consistency; efficient updates. **SCD-1**: `UPDATE dim SET col = new_val WHERE key = X`. **SCD-3**: `UPDATE dim SET prev_col = col, col = new_val, updated = NOW() WHERE key = X`. **MERGE**: `MERGE dim USING staging ON dim.key = staging.key WHEN MATCHED THEN UPDATE SET ...`....

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