*
* Copyright (c) 1994, Regents of the University of California
*
- * $Id: analyze.c,v 1.109 1999/05/25 22:04:25 momjian Exp $
+ * $Id: analyze.c,v 1.110 1999/06/05 20:22:30 tgl Exp $
*
*-------------------------------------------------------------------------
*/
}
/*
- * makeTableName()
- * Create a table name from a list of fields.
+ * makeObjectName()
+ *
+ * Create a name for an implicitly created index, sequence, constraint, etc.
+ *
+ * The parameters are: the original table name, the original field name, and
+ * a "type" string (such as "seq" or "pkey"). The field name and/or type
+ * can be NULL if not relevant.
+ *
+ * The result is a palloc'd string.
+ *
+ * The basic result we want is "name1_name2_type", omitting "_name2" or
+ * "_type" when those parameters are NULL. However, we must generate
+ * a name with less than NAMEDATALEN characters! So, we truncate one or
+ * both names if necessary to make a short-enough string. The type part
+ * is never truncated (so it had better be reasonably short).
+ *
+ * To reduce the probability of collisions, we might someday add more
+ * smarts to this routine, like including some "hash" characters computed
+ * from the truncated characters. Currently it seems best to keep it simple,
+ * so that the generated names are easily predictable by a person.
*/
static char *
-makeTableName(void *elem,...)
+makeObjectName(char *name1, char *name2, char *typename)
{
- va_list args;
-
char *name;
- char buf[NAMEDATALEN + 1];
-
- buf[0] = '\0';
-
- va_start(args, elem);
-
- name = elem;
- while (name != NULL)
+ int overhead = 0; /* chars needed for type and underscores */
+ int availchars; /* chars available for name(s) */
+ int name1chars; /* chars allocated to name1 */
+ int name2chars; /* chars allocated to name2 */
+ int ndx;
+
+ name1chars = strlen(name1);
+ if (name2)
{
- /* not enough room for next part? then return nothing */
- if ((strlen(buf) + strlen(name)) >= (sizeof(buf) - 1))
- return NULL;
+ name2chars = strlen(name2);
+ overhead++; /* allow for separating underscore */
+ }
+ else
+ name2chars = 0;
+ if (typename)
+ overhead += strlen(typename) + 1;
- if (strlen(buf) > 0)
- strcat(buf, "_");
- strcat(buf, name);
+ availchars = NAMEDATALEN-1 - overhead;
- name = va_arg(args, void *);
+ /* If we must truncate, preferentially truncate the longer name.
+ * This logic could be expressed without a loop, but it's simple and
+ * obvious as a loop.
+ */
+ while (name1chars + name2chars > availchars)
+ {
+ if (name1chars > name2chars)
+ name1chars--;
+ else
+ name2chars--;
}
- va_end(args);
-
- name = palloc(strlen(buf) + 1);
- strcpy(name, buf);
+ /* Now construct the string using the chosen lengths */
+ name = palloc(name1chars + name2chars + overhead + 1);
+ strncpy(name, name1, name1chars);
+ ndx = name1chars;
+ if (name2)
+ {
+ name[ndx++] = '_';
+ strncpy(name+ndx, name2, name2chars);
+ ndx += name2chars;
+ }
+ if (typename)
+ {
+ name[ndx++] = '_';
+ strcpy(name+ndx, typename);
+ }
+ else
+ name[ndx] = '\0';
return name;
}
int pass = 0;
char *iname = NULL;
List *ilist;
- IndexStmt *index;
- char name2[NAMEDATALEN + 1];
+ char typename[NAMEDATALEN];
+
+ /* The type name for makeObjectName is label, or labelN if that's
+ * necessary to prevent collisions among multiple indexes for the same
+ * table. Note there is no check for collisions with already-existing
+ * indexes; this ought to be rethought someday.
+ */
+ strcpy(typename, label);
- /* use working storage, since we might be trying several possibilities */
- strcpy(name2, column_name);
- while (iname == NULL)
+ for (;;)
{
- iname = makeTableName(table_name, name2, label, NULL);
- /* unable to make a name at all? then quit */
- if (iname == NULL)
- break;
+ iname = makeObjectName(table_name, column_name, typename);
- ilist = indices;
- while (ilist != NIL)
+ foreach(ilist, indices)
{
- index = lfirst(ilist);
+ IndexStmt *index = lfirst(ilist);
if (strcasecmp(iname, index->idxname) == 0)
break;
-
- ilist = lnext(ilist);
}
/* ran through entire list? then no name conflict found so done */
if (ilist == NIL)
/* the last one conflicted, so try a new name component */
pfree(iname);
- iname = NULL;
- pass++;
- sprintf(name2, "%s_%d", column_name, (pass + 1));
+ sprintf(typename, "%s%d", label, ++pass);
}
return iname;
char *cstring;
CreateSeqStmt *sequence;
- sname = makeTableName(stmt->relname, column->colname, "seq", NULL);
- if (sname == NULL)
- elog(ERROR, "CREATE TABLE/SERIAL implicit sequence name must be less than %d characters"
- "\n\tSum of lengths of '%s' and '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, column->colname, (NAMEDATALEN - 5));
-
+ sname = makeObjectName(stmt->relname, column->colname,
+ "seq");
constraint = makeNode(Constraint);
constraint->contype = CONSTR_DEFAULT;
constraint->name = sname;
constraint = makeNode(Constraint);
constraint->contype = CONSTR_UNIQUE;
- constraint->name = makeTableName(stmt->relname, column->colname, "key", NULL);
- if (constraint->name == NULL)
- elog(ERROR, "CREATE TABLE/SERIAL implicit index name must be less than %d characters"
- "\n\tSum of lengths of '%s' and '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, column->colname, (NAMEDATALEN - 5));
+ constraint->name = makeObjectName(stmt->relname,
+ column->colname,
+ "key");
column->constraints = lappend(column->constraints, constraint);
sequence = makeNode(CreateSeqStmt);
case CONSTR_PRIMARY:
if (constraint->name == NULL)
- constraint->name = makeTableName(stmt->relname, "pkey", NULL);
- if (constraint->name == NULL)
- elog(ERROR, "CREATE TABLE/PRIMARY KEY implicit index name must be less than %d characters"
- "\n\tLength of '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, (NAMEDATALEN - 6));
+ constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
if (constraint->keys == NIL)
constraint->keys = lappend(constraint->keys, column);
dlist = lappend(dlist, constraint);
case CONSTR_UNIQUE:
if (constraint->name == NULL)
- constraint->name = makeTableName(stmt->relname, column->colname, "key", NULL);
- if (constraint->name == NULL)
- elog(ERROR, "CREATE TABLE/UNIQUE implicit index name must be less than %d characters"
- "\n\tLength of '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, (NAMEDATALEN - 5));
+ constraint->name = makeObjectName(stmt->relname, column->colname, "key");
if (constraint->keys == NIL)
constraint->keys = lappend(constraint->keys, column);
dlist = lappend(dlist, constraint);
case CONSTR_CHECK:
constraints = lappend(constraints, constraint);
if (constraint->name == NULL)
- constraint->name = makeTableName(stmt->relname, column->colname, NULL);
- if (constraint->name == NULL)
- elog(ERROR, "CREATE TABLE/CHECK implicit constraint name must be less than %d characters"
- "\n\tSum of lengths of '%s' and '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, column->colname, (NAMEDATALEN - 1));
+ constraint->name = makeObjectName(stmt->relname, column->colname, NULL);
break;
default:
{
case CONSTR_PRIMARY:
if (constraint->name == NULL)
- constraint->name = makeTableName(stmt->relname, "pkey", NULL);
- if (constraint->name == NULL)
- elog(ERROR, "CREATE TABLE/PRIMARY KEY implicit index name must be less than %d characters"
- "\n\tLength of '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, (NAMEDATALEN - 5));
+ constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
dlist = lappend(dlist, constraint);
break;
}
if (constraint->name != NULL)
- index->idxname = constraint->name;
+ index->idxname = pstrdup(constraint->name);
else if (constraint->contype == CONSTR_PRIMARY)
- {
- index->idxname = makeTableName(stmt->relname, "pkey", NULL);
- if (index->idxname == NULL)
- elog(ERROR, "CREATE TABLE/PRIMARY KEY implicit index name must be less than %d characters"
- "\n\tLength of '%s' must be less than %d",
- NAMEDATALEN, stmt->relname, (NAMEDATALEN - 5));
- }
+ index->idxname = makeObjectName(stmt->relname, NULL, "pkey");
else
index->idxname = NULL;
if (constraint->contype == CONSTR_PRIMARY)
column->is_not_null = TRUE;
iparam = makeNode(IndexElem);
- iparam->name = strcpy(palloc(strlen(column->colname) + 1), column->colname);
+ iparam->name = pstrdup(column->colname);
iparam->args = NIL;
iparam->class = NULL;
iparam->typename = NULL;
keys = lnext(keys);
}
- if (index->idxname == NULL)
- elog(ERROR, "CREATE TABLE unable to construct implicit index for table '%s'"
- "; name too long", stmt->relname);
+ if (index->idxname == NULL) /* should not happen */
+ elog(ERROR, "CREATE TABLE: failed to make implicit index name");
ilist = lappend(ilist, index);
dlist = lnext(dlist);
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