diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 1b961e0c1f..d044c7a845 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Consistently quote primary key column names.  #7763 [toolmantim]
+
 * Fixtures: fix YAML ordered map support.  #2665 [Manuel Holtgrewe, nfbuckley]
 
 * DateTimes assume the default timezone.  #7764 [Geoff Buesing]
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 3a9783bac5..f3d4cf856a 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -482,7 +482,7 @@ module ActiveRecord #:nodoc:
       # Deletes the record with the given +id+ without instantiating an object first. If an array of ids is provided, all of them
       # are deleted.
       def delete(id)
-        delete_all([ "#{primary_key} IN (?)", id ])
+        delete_all([ "#{connection.quote_column_name(primary_key)} IN (?)", id ])
       end
 
       # Destroys the record with the given +id+ by instantiating the object and calling #destroy (all the callbacks are the triggered).
@@ -537,9 +537,9 @@ module ActiveRecord #:nodoc:
       def update_counters(id, counters)
         updates = counters.inject([]) { |list, (counter_name, increment)|
           sign = increment < 0 ? "-" : "+"
-          list << "#{counter_name} = #{counter_name} #{sign} #{increment.abs}"
+          list << "#{connection.quote_column_name(counter_name)} = #{connection.quote_column_name(counter_name)} #{sign} #{increment.abs}"
         }.join(", ")
-        update_all(updates, "#{primary_key} = #{quote_value(id)}")
+        update_all(updates, "#{connection.quote_column_name(primary_key)} = #{quote_value(id)}")
       end
 
       # Increments the specified counter by one. So <tt>DiscussionBoard.increment_counter("post_count",
@@ -1047,7 +1047,7 @@ module ActiveRecord #:nodoc:
       
         def find_one(id, options)
           conditions = " AND (#{sanitize_sql(options[:conditions])})" if options[:conditions]
-          options.update :conditions => "#{table_name}.#{primary_key} = #{quote_value(id,columns_hash[primary_key])}#{conditions}"
+          options.update :conditions => "#{table_name}.#{connection.quote_column_name(primary_key)} = #{quote_value(id,columns_hash[primary_key])}#{conditions}"
 
           # Use find_every(options).first since the primary key condition
           # already ensures we have a single record. Using find_initial adds
@@ -1062,7 +1062,7 @@ module ActiveRecord #:nodoc:
         def find_some(ids, options)
           conditions = " AND (#{sanitize_sql(options[:conditions])})" if options[:conditions]
           ids_list   = ids.map { |id| quote_value(id,columns_hash[primary_key]) }.join(',')
-          options.update :conditions => "#{table_name}.#{primary_key} IN (#{ids_list})#{conditions}"
+          options.update :conditions => "#{table_name}.#{connection.quote_column_name(primary_key)} IN (#{ids_list})#{conditions}"
 
           result = find_every(options)
 
@@ -1608,7 +1608,7 @@ module ActiveRecord #:nodoc:
         unless new_record?
           connection.delete <<-end_sql, "#{self.class.name} Destroy"
             DELETE FROM #{self.class.table_name}
-            WHERE #{self.class.primary_key} = #{quoted_id}
+            WHERE #{connection.quote_column_name(self.class.primary_key)} = #{quoted_id}
           end_sql
         end
 
@@ -1847,7 +1847,7 @@ module ActiveRecord #:nodoc:
         connection.update(
           "UPDATE #{self.class.table_name} " +
           "SET #{quoted_comma_pair_list(connection, attributes_with_quotes(false))} " +
-          "WHERE #{self.class.primary_key} = #{quote_value(id)}",
+          "WHERE #{connection.quote_column_name(self.class.primary_key)} = #{quote_value(id)}",
           "#{self.class.name} Update"
         )
       end
diff --git a/activerecord/test/fixtures/db_definitions/db2.drop.sql b/activerecord/test/fixtures/db_definitions/db2.drop.sql
index 50cffe3b47..9837def303 100644
--- a/activerecord/test/fixtures/db_definitions/db2.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/db2.drop.sql
@@ -29,3 +29,4 @@ DROP TABLE fk_test_has_fk;
 DROP TABLE keyboards;
 DROP TABLE legacy_things;
 DROP TABLE numeric_data;
+DROP TABLE mixed_case_monkeys;
diff --git a/activerecord/test/fixtures/db_definitions/db2.sql b/activerecord/test/fixtures/db_definitions/db2.sql
index ee76fc4d05..750e74a0c3 100644
--- a/activerecord/test/fixtures/db_definitions/db2.sql
+++ b/activerecord/test/fixtures/db_definitions/db2.sql
@@ -224,3 +224,8 @@ CREATE TABLE numeric_data (
   my_house_population DECIMAL(2),
   decimal_number_with_default DECIMAL(3,2) DEFAULT 2.78
 );
+
+CREATE TABLE mixed_case_monkeys (
+ monkeyID INT NOT NULL PRIMARY KEY,
+ fleaCount INT
+);
diff --git a/activerecord/test/fixtures/db_definitions/firebird.drop.sql b/activerecord/test/fixtures/db_definitions/firebird.drop.sql
index 2e43243af7..69aa093150 100644
--- a/activerecord/test/fixtures/db_definitions/firebird.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/firebird.drop.sql
@@ -30,6 +30,7 @@ DROP TABLE keyboards;
 DROP TABLE defaults;
 DROP TABLE legacy_things;
 DROP TABLE numeric_data;
+DROP TABLE mixed_case_monkeys;
 
 DROP DOMAIN D_BOOLEAN;
 
@@ -59,3 +60,4 @@ DROP GENERATOR keyboards_seq;
 DROP GENERATOR defaults_seq;
 DROP GENERATOR legacy_things_seq;
 DROP GENERATOR numeric_data_seq;
+DROP GENERATOR mixed_case_monkeys_seq;
\ No newline at end of file
diff --git a/activerecord/test/fixtures/db_definitions/firebird.sql b/activerecord/test/fixtures/db_definitions/firebird.sql
index 8ca0bf6222..779701c354 100644
--- a/activerecord/test/fixtures/db_definitions/firebird.sql
+++ b/activerecord/test/fixtures/db_definitions/firebird.sql
@@ -295,3 +295,10 @@ CREATE TABLE numeric_data (
 );
 CREATE GENERATOR numeric_data_seq;
 SET GENERATOR numeric_data_seq TO 10000;
+
+CREATE TABLE mixed_case_monkeys (
+ "monkeyID" BIGINT NOT NULL,
+ "fleaCount" INTEGER
+);
+CREATE GENERATOR mixed_case_monkeys_seq;
+SET GENERATOR mixed_case_monkeys_seq TO 10000;
diff --git a/activerecord/test/fixtures/db_definitions/frontbase.drop.sql b/activerecord/test/fixtures/db_definitions/frontbase.drop.sql
index 5fc64f769b..1c87fdf7ed 100644
--- a/activerecord/test/fixtures/db_definitions/frontbase.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/frontbase.drop.sql
@@ -29,3 +29,4 @@ DROP TABLE fk_test_has_pk CASCADE;
 DROP TABLE keyboards CASCADE;
 DROP TABLE legacy_things CASCADE;
 DROP TABLE numeric_data CASCADE;
+DROP TABLE mixed_case_monkeys CASCADE;
diff --git a/activerecord/test/fixtures/db_definitions/frontbase.sql b/activerecord/test/fixtures/db_definitions/frontbase.sql
index e102f65aa7..798b0204d2 100644
--- a/activerecord/test/fixtures/db_definitions/frontbase.sql
+++ b/activerecord/test/fixtures/db_definitions/frontbase.sql
@@ -260,3 +260,9 @@ CREATE TABLE "numeric_data" (
   primary key ("id")
 );
 SET UNIQUE FOR numeric_data(id);
+
+CREATE TABLE mixed_case_monkeys (
+ "monkeyID" integer DEFAULT unique,
+ "fleaCount" integer
+);
+SET UNIQUE FOR mixed_case_monkeys("monkeyID");
diff --git a/activerecord/test/fixtures/db_definitions/mysql.drop.sql b/activerecord/test/fixtures/db_definitions/mysql.drop.sql
index cb6a870a7c..f269b3a3b7 100644
--- a/activerecord/test/fixtures/db_definitions/mysql.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/mysql.drop.sql
@@ -29,3 +29,4 @@ DROP TABLE fk_test_has_pk;
 DROP TABLE keyboards;
 DROP TABLE legacy_things;
 DROP TABLE numeric_data;
+DROP TABLE mixed_case_monkeys;
diff --git a/activerecord/test/fixtures/db_definitions/mysql.sql b/activerecord/test/fixtures/db_definitions/mysql.sql
index 8a56ab2172..1450d20890 100755
--- a/activerecord/test/fixtures/db_definitions/mysql.sql
+++ b/activerecord/test/fixtures/db_definitions/mysql.sql
@@ -226,3 +226,9 @@ CREATE TABLE `numeric_data` (
   `my_house_population` decimal(2),
   `decimal_number_with_default` decimal(3,2) DEFAULT 2.78
 ) TYPE=InnoDB;
+
+CREATE TABLE mixed_case_monkeys (
+ `monkeyID` int(11) NOT NULL auto_increment,
+ `fleaCount` int(11),
+ PRIMARY KEY (`monkeyID`)
+) TYPE=InnoDB;
diff --git a/activerecord/test/fixtures/db_definitions/openbase.sql b/activerecord/test/fixtures/db_definitions/openbase.sql
index c3da2efee6..4f5d27e63d 100644
--- a/activerecord/test/fixtures/db_definitions/openbase.sql
+++ b/activerecord/test/fixtures/db_definitions/openbase.sql
@@ -292,3 +292,11 @@ CREATE TABLE numeric_data (
 go
 CREATE PRIMARY KEY numeric_data (id)
 go
+
+CREATE TABLE mixed_case_monkeys (
+  monkeyID INTEGER NOT NULL DEFAULT _rowid,
+  fleaCount INTEGER
+);
+go
+CREATE PRIMARY KEY mixed_case_monkeys (monkeyID)
+go
diff --git a/activerecord/test/fixtures/db_definitions/oracle.drop.sql b/activerecord/test/fixtures/db_definitions/oracle.drop.sql
index 6fa01cdf51..910b118e05 100644
--- a/activerecord/test/fixtures/db_definitions/oracle.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/oracle.drop.sql
@@ -30,6 +30,7 @@ drop table fk_test_has_fk;
 drop table keyboards;
 drop table legacy_things;
 drop table numeric_data;
+drop table mixed_case_monkeys;
 
 drop sequence accounts_seq;
 drop sequence funny_jokes_seq;
@@ -61,3 +62,4 @@ drop sequence fk_test_has_fk_seq;
 drop sequence keyboards_seq;
 drop sequence legacy_things_seq;
 drop sequence numeric_data_seq;
+drop sequence mixed_case_monkeys_seq;
diff --git a/activerecord/test/fixtures/db_definitions/oracle.sql b/activerecord/test/fixtures/db_definitions/oracle.sql
index 869c59fb75..f84a86a655 100644
--- a/activerecord/test/fixtures/db_definitions/oracle.sql
+++ b/activerecord/test/fixtures/db_definitions/oracle.sql
@@ -317,3 +317,9 @@ CREATE TABLE numeric_data (
   decimal_number_with_default decimal(3,2) DEFAULT 2.78
 );
 create sequence numeric_data_seq minvalue 10000;
+
+CREATE TABLE mixed_case_monkeys (
+ "monkeyID" INTEGER NOT NULL PRIMARY KEY,
+ "fleaCount" INTEGER
+);
+create sequence mixed_case_monkeys_seq minvalue 10000;
diff --git a/activerecord/test/fixtures/db_definitions/postgresql.drop.sql b/activerecord/test/fixtures/db_definitions/postgresql.drop.sql
index 4910b0ecee..3afe6d39a9 100644
--- a/activerecord/test/fixtures/db_definitions/postgresql.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/postgresql.drop.sql
@@ -34,3 +34,4 @@ DROP TABLE keyboards;
 DROP TABLE legacy_things;
 DROP TABLE numeric_data;
 DROP TABLE column_data;
+DROP TABLE mixed_case_monkeys;
diff --git a/activerecord/test/fixtures/db_definitions/postgresql.sql b/activerecord/test/fixtures/db_definitions/postgresql.sql
index 18f2ededeb..15a61ea8c4 100644
--- a/activerecord/test/fixtures/db_definitions/postgresql.sql
+++ b/activerecord/test/fixtures/db_definitions/postgresql.sql
@@ -240,3 +240,8 @@ CREATE TABLE numeric_data (
   my_house_population decimal(2),
   decimal_number_with_default decimal(3,2) default 2.78
 );
+
+CREATE TABLE mixed_case_monkeys (
+ "monkeyID" INTEGER PRIMARY KEY,
+ "fleaCount" INTEGER
+);
diff --git a/activerecord/test/fixtures/db_definitions/sqlite.drop.sql b/activerecord/test/fixtures/db_definitions/sqlite.drop.sql
index cb6a870a7c..f269b3a3b7 100644
--- a/activerecord/test/fixtures/db_definitions/sqlite.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/sqlite.drop.sql
@@ -29,3 +29,4 @@ DROP TABLE fk_test_has_pk;
 DROP TABLE keyboards;
 DROP TABLE legacy_things;
 DROP TABLE numeric_data;
+DROP TABLE mixed_case_monkeys;
diff --git a/activerecord/test/fixtures/db_definitions/sqlite.sql b/activerecord/test/fixtures/db_definitions/sqlite.sql
index edf1e815da..973639f177 100644
--- a/activerecord/test/fixtures/db_definitions/sqlite.sql
+++ b/activerecord/test/fixtures/db_definitions/sqlite.sql
@@ -208,3 +208,8 @@ CREATE TABLE 'numeric_data' (
   'my_house_population' DECIMAL(2),
   'decimal_number_with_default' DECIMAL(3,2) DEFAULT 2.78
 );
+
+CREATE TABLE mixed_case_monkeys (
+ 'monkeyID' INTEGER NOT NULL PRIMARY KEY,
+ 'fleaCount' INTEGER
+);
diff --git a/activerecord/test/fixtures/db_definitions/sqlserver.drop.sql b/activerecord/test/fixtures/db_definitions/sqlserver.drop.sql
index e8327f0826..c415d223f5 100644
--- a/activerecord/test/fixtures/db_definitions/sqlserver.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/sqlserver.drop.sql
@@ -31,3 +31,4 @@ DROP TABLE keyboards;
 DROP TABLE legacy_things;
 DROP TABLE numeric_data;
 DROP TABLE [order];
+DROP TABLE mixed_case_monkeys;
diff --git a/activerecord/test/fixtures/db_definitions/sqlserver.sql b/activerecord/test/fixtures/db_definitions/sqlserver.sql
index 50e1938d0a..3cec4e4a16 100644
--- a/activerecord/test/fixtures/db_definitions/sqlserver.sql
+++ b/activerecord/test/fixtures/db_definitions/sqlserver.sql
@@ -236,3 +236,8 @@ CREATE TABLE [order] (
   texture varchar(255),
   flavor varchar(255)
 );
+
+CREATE TABLE mixed_case_monkeys (
+  [monkeyID] int NOT NULL IDENTITY(1, 1),
+  [fleaCount] int default NULL
+);
diff --git a/activerecord/test/fixtures/db_definitions/sybase.drop.sql b/activerecord/test/fixtures/db_definitions/sybase.drop.sql
index ebf2fc9736..9d85221610 100644
--- a/activerecord/test/fixtures/db_definitions/sybase.drop.sql
+++ b/activerecord/test/fixtures/db_definitions/sybase.drop.sql
@@ -29,5 +29,6 @@ DROP TABLE fk_test_has_pk
 DROP TABLE keyboards
 DROP TABLE legacy_things
 DROP TABLE numeric_data
+DROP TABLE mixed_case_monkeys
 DROP TABLE schema_info
 go
diff --git a/activerecord/test/fixtures/db_definitions/sybase.sql b/activerecord/test/fixtures/db_definitions/sybase.sql
index 8544a4150e..6c42c66031 100644
--- a/activerecord/test/fixtures/db_definitions/sybase.sql
+++ b/activerecord/test/fixtures/db_definitions/sybase.sql
@@ -210,4 +210,9 @@ CREATE TABLE numeric_data (
   decimal_number_with_default numeric(3,2) DEFAULT 2.78
 )
 
+CREATE TABLE mixed_case_monkeys (
+  [monkeyID] numeric(9,0) IDENTITY PRIMARY KEY,
+  [fleaCount] numeric(9,0)
+);
+
 go
diff --git a/activerecord/test/fixtures/mixed_case_monkey.rb b/activerecord/test/fixtures/mixed_case_monkey.rb
new file mode 100644
index 0000000000..853f2682b3
--- /dev/null
+++ b/activerecord/test/fixtures/mixed_case_monkey.rb
@@ -0,0 +1,3 @@
+class MixedCaseMonkey < ActiveRecord::Base
+  set_primary_key 'monkeyID'
+end
diff --git a/activerecord/test/fixtures/mixed_case_monkeys.yml b/activerecord/test/fixtures/mixed_case_monkeys.yml
new file mode 100644
index 0000000000..eecd448f4b
--- /dev/null
+++ b/activerecord/test/fixtures/mixed_case_monkeys.yml
@@ -0,0 +1,6 @@
+first:
+  monkeyID: 1
+  fleaCount: 42
+second:
+  monkeyID: 2
+  fleaCount: 43
diff --git a/activerecord/test/pk_test.rb b/activerecord/test/pk_test.rb
index 604b263571..4daef43062 100644
--- a/activerecord/test/pk_test.rb
+++ b/activerecord/test/pk_test.rb
@@ -4,9 +4,10 @@ require 'fixtures/reply'
 require 'fixtures/subscriber'
 require 'fixtures/movie'
 require 'fixtures/keyboard'
+require 'fixtures/mixed_case_monkey'
 
 class PrimaryKeysTest < Test::Unit::TestCase
-  fixtures :topics, :subscribers, :movies
+  fixtures :topics, :subscribers, :movies, :mixed_case_monkeys
 
   def test_integer_key
     topic = Topic.find(1)
@@ -78,4 +79,23 @@ class PrimaryKeysTest < Test::Unit::TestCase
     Topic.reset_primary_key
     assert_equal "id", Topic.primary_key
   end
+  
+  def test_delete_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.delete(1) }
+  end
+  def test_update_counters_should_quote_pkey_and_quote_counter_columns
+    assert_nothing_raised { MixedCaseMonkey.update_counters(1, :fleaCount => 99) }
+  end
+  def test_find_with_one_id_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1) }
+  end
+  def test_find_with_multiple_ids_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find([1,2]) }
+  end
+  def test_instance_update_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1).save }
+  end
+  def test_instance_destry_should_quote_pkey
+    assert_nothing_raised { MixedCaseMonkey.find(1).destroy }
+  end
 end