diff --git a/src/db.c b/src/db.c
index aaf6fe2..6566527 100644
--- a/src/db.c
+++ b/src/db.c
@@ -26,15 +26,15 @@
 #include "db.h"
 
 static const char *stmt_sql[] = {
-	[SEL_BY_IMSI] = "SELECT id,imsi,msisdn,vlr_number,sgsn_number,sgsn_address,periodic_lu_tmr,periodic_rau_tau_tmr,nam_cs,nam_ps,lmsi,ms_purged_cs,ms_purged_ps FROM subscriber WHERE imsi = ?",
-	[UPD_VLR_BY_ID] = "UPDATE subscriber SET vlr_number = ? WHERE id = ?",
-	[UPD_SGSN_BY_ID] = "UPDATE subscriber SET sgsn_number = ? WHERE id = ?",
-	[AUC_BY_IMSI] = "SELECT id, algo_id_2g, ki, algo_id_3g, k, op, opc, sqn, ind_bitlen FROM subscriber LEFT JOIN auc_2g ON auc_2g.subscriber_id = subscriber.id LEFT JOIN auc_3g ON auc_3g.subscriber_id = subscriber.id WHERE imsi = ?",
-	[AUC_UPD_SQN] = "UPDATE auc_3g SET sqn = ? WHERE subscriber_id = ?",
-	[UPD_PURGE_CS_BY_IMSI] = "UPDATE subscriber SET ms_purged_cs=1 WHERE imsi = ?",
-	[UPD_PURGE_PS_BY_IMSI] = "UPDATE subscriber SET ms_purged_ps=1 WHERE imsi = ?",
-	[SET_NAM_PS_BY_IMSI] = "UPDATE subscriber SET nam_ps=1 WHERE imsi = ?",
-	[UNSET_NAM_PS_BY_IMSI] = "UPDATE subscriber SET nam_ps=0 WHERE imsi = ?",
+	[DB_STMT_SEL_BY_IMSI] = "SELECT id,imsi,msisdn,vlr_number,sgsn_number,sgsn_address,periodic_lu_tmr,periodic_rau_tau_tmr,nam_cs,nam_ps,lmsi,ms_purged_cs,ms_purged_ps FROM subscriber WHERE imsi = ?",
+	[DB_STMT_UPD_VLR_BY_ID] = "UPDATE subscriber SET vlr_number = ? WHERE id = ?",
+	[DB_STMT_UPD_SGSN_BY_ID] = "UPDATE subscriber SET sgsn_number = ? WHERE id = ?",
+	[DB_STMT_AUC_BY_IMSI] = "SELECT id, algo_id_2g, ki, algo_id_3g, k, op, opc, sqn, ind_bitlen FROM subscriber LEFT JOIN auc_2g ON auc_2g.subscriber_id = subscriber.id LEFT JOIN auc_3g ON auc_3g.subscriber_id = subscriber.id WHERE imsi = ?",
+	[DB_STMT_AUC_UPD_SQN] = "UPDATE auc_3g SET sqn = ? WHERE subscriber_id = ?",
+	[DB_STMT_UPD_PURGE_CS_BY_IMSI] = "UPDATE subscriber SET ms_purged_cs=1 WHERE imsi = ?",
+	[DB_STMT_UPD_PURGE_PS_BY_IMSI] = "UPDATE subscriber SET ms_purged_ps=1 WHERE imsi = ?",
+	[DB_STMT_SET_NAM_PS_BY_IMSI] = "UPDATE subscriber SET nam_ps=1 WHERE imsi = ?",
+	[DB_STMT_UNSET_NAM_PS_BY_IMSI] = "UPDATE subscriber SET nam_ps=0 WHERE imsi = ?",
 };
 
 static void sql3_error_log_cb(void *arg, int err_code, const char *msg)
diff --git a/src/db.h b/src/db.h
index a60cf62..d424b38 100644
--- a/src/db.h
+++ b/src/db.h
@@ -4,22 +4,22 @@
 #include <sqlite3.h>
 
 enum stmt_idx {
-	SEL_BY_IMSI		= 0,
-	UPD_VLR_BY_ID		= 1,
-	UPD_SGSN_BY_ID		= 2,
-	AUC_BY_IMSI		= 3,
-	AUC_UPD_SQN		= 4,
-	UPD_PURGE_CS_BY_IMSI	= 5,
-	UPD_PURGE_PS_BY_IMSI	= 6,
-	SET_NAM_PS_BY_IMSI	= 7,
-	UNSET_NAM_PS_BY_IMSI	= 8,
-	_NUM_STMT
+	DB_STMT_SEL_BY_IMSI,
+	DB_STMT_UPD_VLR_BY_ID,
+	DB_STMT_UPD_SGSN_BY_ID,
+	DB_STMT_AUC_BY_IMSI,
+	DB_STMT_AUC_UPD_SQN,
+	DB_STMT_UPD_PURGE_CS_BY_IMSI,
+	DB_STMT_UPD_PURGE_PS_BY_IMSI,
+	DB_STMT_SET_NAM_PS_BY_IMSI,
+	DB_STMT_UNSET_NAM_PS_BY_IMSI,
+	_NUM_DB_STMT
 };
 
 struct db_context {
 	char *fname;
 	sqlite3 *db;
-	sqlite3_stmt *stmt[_NUM_STMT];
+	sqlite3_stmt *stmt[_NUM_DB_STMT];
 };
 
 bool db_remove_reset(sqlite3_stmt *stmt);
diff --git a/src/db_auc.c b/src/db_auc.c
index f532b83..07039d4 100644
--- a/src/db_auc.c
+++ b/src/db_auc.c
@@ -36,7 +36,7 @@
 int db_update_sqn(struct db_context *dbc, uint64_t id,
 		      uint64_t new_sqn)
 {
-	sqlite3_stmt *stmt = dbc->stmt[AUC_UPD_SQN];
+	sqlite3_stmt *stmt = dbc->stmt[DB_STMT_AUC_UPD_SQN];
 	int rc;
 
 	/* bind new SQN and subscriber ID */
@@ -79,7 +79,7 @@
 		     struct osmo_sub_auth_data *aud3g,
 		     uint64_t *subscr_id)
 {
-	sqlite3_stmt *stmt = dbc->stmt[AUC_BY_IMSI];
+	sqlite3_stmt *stmt = dbc->stmt[DB_STMT_AUC_BY_IMSI];
 	int ret = 0;
 	int rc;
 
diff --git a/src/db_hlr.c b/src/db_hlr.c
index f6ae18f..9c74a24 100644
--- a/src/db_hlr.c
+++ b/src/db_hlr.c
@@ -40,7 +40,7 @@
 int db_subscr_get(struct db_context *dbc, const char *imsi,
 		  struct hlr_subscriber *subscr)
 {
-	sqlite3_stmt *stmt = dbc->stmt[SEL_BY_IMSI];
+	sqlite3_stmt *stmt = dbc->stmt[DB_STMT_SEL_BY_IMSI];
 	int rc;
 
 	if (!db_bind_imsi(stmt, imsi))
@@ -83,7 +83,7 @@
 int db_subscr_ps(struct db_context *dbc, const char *imsi, bool enable)
 {
 	sqlite3_stmt *stmt =
-		dbc->stmt[enable ? SET_NAM_PS_BY_IMSI : UNSET_NAM_PS_BY_IMSI];
+		dbc->stmt[enable ? DB_STMT_SET_NAM_PS_BY_IMSI : DB_STMT_UNSET_NAM_PS_BY_IMSI];
 	int rc;
 
 	if (!db_bind_imsi(stmt, imsi))
@@ -111,15 +111,15 @@
 		 const struct hlr_subscriber *subscr,
 		 const char *vlr_or_sgsn_number, bool lu_is_ps)
 {
-	sqlite3_stmt *stmt = dbc->stmt[UPD_VLR_BY_ID];
+	sqlite3_stmt *stmt = dbc->stmt[DB_STMT_UPD_VLR_BY_ID];
 	const char *txt;
 	int rc, ret = 0;
 
 	if (lu_is_ps) {
-		stmt = dbc->stmt[UPD_SGSN_BY_ID];
+		stmt = dbc->stmt[DB_STMT_UPD_SGSN_BY_ID];
 		txt = subscr->sgsn_number;
 	} else {
-		stmt = dbc->stmt[UPD_VLR_BY_ID];
+		stmt = dbc->stmt[DB_STMT_UPD_VLR_BY_ID];
 		txt = subscr->vlr_number;
 	}
 
@@ -150,13 +150,13 @@
 
 int db_subscr_purge(struct db_context *dbc, const char *imsi, bool is_ps)
 {
-	sqlite3_stmt *stmt = dbc->stmt[UPD_VLR_BY_ID];
+	sqlite3_stmt *stmt = dbc->stmt[DB_STMT_UPD_VLR_BY_ID];
 	int rc, ret = 1;
 
 	if (is_ps)
-		stmt = dbc->stmt[UPD_PURGE_PS_BY_IMSI];
+		stmt = dbc->stmt[DB_STMT_UPD_PURGE_PS_BY_IMSI];
 	else
-		stmt = dbc->stmt[UPD_PURGE_CS_BY_IMSI];
+		stmt = dbc->stmt[DB_STMT_UPD_PURGE_CS_BY_IMSI];
 
 	if (!db_bind_imsi(stmt, imsi))
 		return -EINVAL;