PATTERN Cited by 1 source

Parameterized template execution with entity validation

When a natural-language request selects a query template, extract only the values required by that template, validate each against its slot contract, and bind validated values as database parameters. Never interpolate entity text into the SQL syntax. The structure is especially useful for Text2SQL fast paths, where an LLM or NER model provides values but must not control query construction. (Source: sources/2026-08-13-aws-reducing-text2sql-latency-with-parameterized-query-templates)

Flow

selected template: SELECT ... WHERE quarter = {quarter}
question:          "Show me Q3 sales"
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entity extraction: {quarter: "Q3"}
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slot validation:   Q3 ∈ allowed quarter values
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prepared bind:     SELECT ... WHERE quarter = ?   params = ["Q3"]
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live database execution

Two independent safeguards

1. Semantic/format validation. {quarter} must be a recognized quarter, {date} must parse to an expected date type, and a numeric threshold must be numeric and within applicable policy limits. This detects extraction mistakes before database access.
2. Prepared-statement binding. Parameters are transmitted as data rather than concatenated into executable SQL, preventing a value from changing query syntax.

Both are necessary: prepared statements alone do not ensure that a correctly typed but semantically wrong entity answers the user's request; validation alone is not a substitute for safe query binding. (Source: sources/2026-08-13-aws-reducing-text2sql-latency-with-parameterized-query-templates)

Boundaries

This pattern protects literal slots, not every query safety concern. It must be combined with read-only credentials, tenant and authorization filters, allowlisted template ownership, query-cost controls, and result sufficiency checks. Identifiers such as table or column names cannot generally be safely parameterized and should come from vetted templates rather than model output.

Seen in

• sources/2026-08-13-aws-reducing-text2sql-latency-with-parameterized-query-templates — entity-extraction and parameter-binding layer for a semantic Text2SQL template cache.

Related

• patterns/explain-before-execute-validation — validates generated SQL structure before running it; this pattern validates values within an already-vetted structure.
• patterns/semantic-template-cache-with-generative-fallback — upstream selection and fallback flow.
• concepts/query-structure-caching — the reusable artifact being safely materialized.