 	PRIMARY KEY(id),
 	KEY biological_sample_idx(biological_sample_id),
 	KEY parameter_idx(parameter_id),
-	KEY observation_type_idx(observation_type)
+	KEY population_idx(population_id)
 
 ) COLLATE=utf8_general_ci ENGINE=MyISAM;
 

--
-- Drop all the tables if they exist
--
DROP TABLE IF EXISTS allele;
DROP TABLE IF EXISTS biological_model;
DROP TABLE IF EXISTS biological_model_allele;

) COLLATE=utf8_general_ci ENGINE=MyISAM;

/**
 * Genomic feature cross-reference from other datasources.
 */
CREATE TABLE xref (

    id                        INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    acc                       VARCHAR(20) NOT NULL,
    db_id                     INT(10) NOT NULL,
    xref_acc                  VARCHAR(20) NOT NULL,
    xref_db_id                INT(10) NOT NULL,
    
    PRIMARY KEY (id),
    KEY genomic_feature_idx (acc, db_id),
    KEY xref_idx (xref_acc, xref_db_id)
    
) COLLATE=utf8_general_ci ENGINE=MyISAM;

/**
 * Allele table
 * Contains sequence variant of a gene recognized by a DNA assay (polymorphic)
 * or a variant phenotype (mutant)
