export type QueryType = 'SELECT' | 'SHOW' | 'DESCRIBE' | 'UPDATE' | 'DELETE' | 'INSERT' | 'CREATE' | 'DROP' | 'ALTER' | 'MERGE' | 'UNKNOWN';
export interface ValidationResult {
    isValid: boolean;
    queryType: QueryType;
    error?: string;
}
/**
 * Validates SQL queries for security and permission constraints
 */
export declare class QueryValidator {
    private readonly enableUpdates;
    constructor(enableUpdates?: boolean);
    /**
     * Validates a SQL query based on the current security settings
     * @param sql - SQL query to validate
     * @returns Validation result with query type and any errors
     */
    validate(sql: string): ValidationResult;
    /**
     * Detects the type of SQL query
     */
    private detectQueryType;
    /**
     * Checks if a SQL fragment contains write operations
     */
    private containsWriteOperations;
    /**
     * Checks if a query type is read-only
     * @param queryType - Type of query to check
     * @returns true if the query type is read-only
     */
    isReadOnly(queryType: QueryType): boolean;
    /**
     * Checks if a query type is a write operation
     * @param queryType - Type of query to check
     * @returns true if the query type is a write operation
     */
    isWriteOperation(queryType: QueryType): boolean;
}
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