diff --git a/tdbcmysql/generic/tdbcmysql.c b/tdbcmysql/generic/tdbcmysql.c
index 27e375e..506142e 100644
--- a/tdbcmysql/generic/tdbcmysql.c
+++ b/tdbcmysql/generic/tdbcmysql.c
@@ -2638,7 +2638,7 @@ StatementParamtypeMethod(
     StatementData* sdata	/* The current statement */
 	= (StatementData*) Tcl_ObjectGetMetadata(thisObject,
 						 &statementDataType);
-    struct {
+    static const struct {
 	const char* name;
 	int flags;
     } directions[] = {
@@ -2853,7 +2853,6 @@ ResultSetConstructor(
     int skip = Tcl_ObjectContextSkippedArgs(context);
 				/* Number of args to skip */
     Tcl_Object statementObject;	/* The current statement object */
-    PerInterpData* pidata;	/* The per-interpreter data for this package */
     ConnectionData* cdata;	/* The MySQL connection object's data */
     StatementData* sdata;	/* The statement object's data */
     ResultSetData* rdata;	/* THe result set object's data */
@@ -2911,7 +2910,6 @@ ResultSetConstructor(
 	}
 	cdata->flags |= CONN_FLAG_AUTOCOMMIT;
     }
-    pidata = cdata->pidata;
 
     /* Allocate an object to hold data about this result set */
 
diff --git a/tdbcodbc/generic/tdbcodbc.c b/tdbcodbc/generic/tdbcodbc.c
index c89ffc4..f179f92 100644
--- a/tdbcodbc/generic/tdbcodbc.c
+++ b/tdbcodbc/generic/tdbcodbc.c
@@ -973,6 +973,9 @@ SQLStateIs(
  * Side effects:
  *	If successful, stores the enumerated value in '*valuePtr'
  *
+ * Notes:
+ *	The 'table' argument must be constant and statically allocated.
+ *
  *-----------------------------------------------------------------------------
  */
 
@@ -3124,7 +3127,7 @@ ForeignkeysStatementConstructor(
     StatementData* sdata;	/* The statement's object data */
     RETCODE rc;			/* Return code from ODBC */
 
-    const char* options[] = {	/* Option table */
+    const static char* options[] = {	/* Option table */
 	"-foreign",
 	"-primary",
 	NULL
diff --git a/tdbcpostgres/generic/tdbcpostgres.c b/tdbcpostgres/generic/tdbcpostgres.c
index 968aec0..0a64a7e 100644
--- a/tdbcpostgres/generic/tdbcpostgres.c
+++ b/tdbcpostgres/generic/tdbcpostgres.c
@@ -2341,7 +2341,7 @@ StatementParamtypeMethod(
     StatementData* sdata	/* The current statement */
 	= (StatementData*) Tcl_ObjectGetMetadata(thisObject,
 						 &statementDataType);
-    struct {
+    static const struct {
 	const char* name;
 	int flags;
     } directions[] = {