If more than half of the tables have the same primary key then it's m…

…ost likely a database where primary key names aren't unique

src/net/sourceforge/schemaspy/DBAnalyzer.java

@@ -31,13 +31,16 @@ public int compare(Object object1, Object object2) {
 	    }
 	});
 
+        int duplicatePrimaries = 0;
+
         // gather all the primary key columns and columns without parents
 	for (Iterator iter = tables.iterator(); iter.hasNext(); ) {
 	    Table table = (Table)iter.next();
 	    List tablePrimaries = table.getPrimaryColumns();
             if (tablePrimaries.size() == 1) { // can't match up multiples...yet...
                 for (Iterator primariesIter = tablePrimaries.iterator(); primariesIter.hasNext(); ) {
-                    allPrimaries.put(primariesIter.next(), table);
+                    if (allPrimaries.put(primariesIter.next(), table) != null)
+                        ++duplicatePrimaries;
                 }
             }
 
@@ -48,6 +51,12 @@ public int compare(Object object1, Object object2) {
 	    }
 	}
 
+        // if more than half of the tables have the same primary key then
+        // it's most likey a database where primary key names aren't unique
+        // (e.g. they all have a primary key named 'ID')
+        if (duplicatePrimaries > allPrimaries.size())
+            return new ArrayList();
+
 	sortColumnsByTable(columnsWithoutParents);
 
 	List impliedConstraints = new ArrayList();

src/net/sourceforge/schemaspy/Main.java

@@ -161,7 +161,7 @@ else if (maxThreads == 0)
                 StyleSheet.write(out);
                 out.close();
                 out = new LineWriter(new FileWriter(new File(outputDir, "schemaSpy.js")));
-                new JavaScriptFormatter().write(out);
+                JavaScriptFormatter.write(out);
                 out.close();
 
                 startSummarizing = System.currentTimeMillis();

src/net/sourceforge/schemaspy/model/ImpliedForeignKeyConstraint.java

@@ -1,9 +1,7 @@
 package net.sourceforge.schemaspy.model;
 
-import java.io.Serializable;
-import java.sql.SQLException;
-import java.util.Collections;
-import java.util.List;
+import java.io.*;
+import java.sql.*;
 
 public class ImpliedForeignKeyConstraint extends ForeignKeyConstraint implements Serializable {
     public ImpliedForeignKeyConstraint(TableColumn parentColumn, TableColumn childColumn) throws SQLException {

src/net/sourceforge/schemaspy/view/JavaScriptFormatter.java

@@ -4,7 +4,7 @@
 import net.sourceforge.schemaspy.util.LineWriter;
 
 public class JavaScriptFormatter {
-    public void write(LineWriter out) throws IOException {
+    public static void write(LineWriter out) throws IOException {
         out.writeln("function toggle(styleIndex) {");
         out.writeln("  var rules = document.styleSheets[0].cssRules;");
         out.writeln("  if (rules == null) rules = document.styleSheets[0].rules;");