sql / intermediate
Snippet
Enforcing Uniqueness Across Combined Attributes via Unique Index
A multi-column unique index ensures that the combination of values in the specified columns remains distinct across all rows. It simultaneously enforces data integrity constraints and optimizes multi-column lookup queries.
snippet.sql
sql
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CREATE UNIQUE INDEX idx_unique_tenant_emailON users (tenant_id, email_address);
Breakdown
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CREATE UNIQUE INDEX idx_unique_tenant_email
Creates a new index that rejects duplicate entries for indexed column combinations.
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ON users (tenant_id, email_address);
Applies the composite uniqueness rule across 'tenant_id' and 'email_address' on 'users'.