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From 8812b05e24aeb70099e50bb2716b647555902365 Mon Sep 17 00:00:00 2001
From: Praveen Devarao <praveen@falcon>
Date: Thu, 25 Feb 2010 12:49:19 +0530
Subject: [PATCH] Moved adding of limit on deletion and adding of limit on update conditions to GenericCompiler, to provide flexibility to handle db specifics
---
lib/arel/engines/sql/compilers/ibm_db_compiler.rb | 62 +++++++++++++++++++++
lib/arel/engines/sql/relations/compiler.rb | 7 ++-
lib/arel/engines/sql/relations/writes.rb | 6 +-
3 files changed, 70 insertions(+), 5 deletions(-)
create mode 100644 lib/arel/engines/sql/compilers/ibm_db_compiler.rb
diff --git a/lib/arel/engines/sql/compilers/ibm_db_compiler.rb b/lib/arel/engines/sql/compilers/ibm_db_compiler.rb
new file mode 100644
index 0000000..e6be73d
--- /dev/null
+++ b/lib/arel/engines/sql/compilers/ibm_db_compiler.rb
@@ -0,0 +1,62 @@
+# +-----------------------------------------------------------------------+
+# | |
+# | Copyright (c) 2010 IBM Corporation |
+# | |
+# | Permission is hereby granted, free of charge, to any person obtaining |
+# | a copy of this software and associated documentation files (the |
+# | "Software"), to deal in the Software without restriction, including |
+# | without limitation the rights to use, copy, modify, merge, publish, |
+# | distribute, sublicense, and/or sell copies of the Software, and to |
+# | permit persons to whom the Software is furnished to do so, subject to |
+# | the following conditions: |
+# | |
+# | The above copyright notice and this permission notice shall be |
+# | included in all copies or substantial portions of the Software. |
+# | |
+# | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
+# | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
+# | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.|
+# | IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR |
+# | ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
+# | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
+# | WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
+# | |
+# +-----------------------------------------------------------------------+
+
+#
+# Author: Praveen Devarao <praveendrl@in.ibm.com>
+#
+
+module Arel
+ module SqlCompiler
+ class IBM_DBCompiler < GenericCompiler
+
+ def select_sql
+ query = build_query \
+ "SELECT #{select_clauses.join(', ')}",
+ "FROM #{from_clauses}",
+ (joins(self) unless joins(self).blank? ),
+ ("WHERE #{where_clauses.join(" AND ")}" unless wheres.blank? ),
+ ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ),
+ ("HAVING #{having_clauses.join(', ')}" unless havings.blank? ),
+ ("ORDER BY #{order_clauses.join(', ')}" unless orders.blank? )
+ engine.add_limit_offset!(query,{:limit=>taken,:offset=>skipped}) unless taken.blank?
+ query << "#{locked}" unless locked.blank?
+ query
+ end
+
+ def limited_update_conditions(conditions, taken)
+ quoted_primary_key = engine.quote_table_name(primary_key)
+ update_conditions = "WHERE #{quoted_primary_key} IN (SELECT #{quoted_primary_key} FROM #{engine.connection.quote_table_name table.name} #{conditions} " #Note: - ')' not added, limit segment is to be appended
+ engine.add_limit_offset!(update_conditions,{:limit=>taken,:offset=>nil})
+ update_conditions << ")" # Close the sql segment
+ update_conditions
+ end
+
+ def add_limit_on_delete(taken)
+ "" # Limiting the number of rows to be deleted is not supported by IBM_DB
+ end
+
+ end
+ end
+end
diff --git a/lib/arel/engines/sql/relations/compiler.rb b/lib/arel/engines/sql/relations/compiler.rb
index c974e43..597ed88 100644
--- a/lib/arel/engines/sql/relations/compiler.rb
+++ b/lib/arel/engines/sql/relations/compiler.rb
@@ -21,11 +21,16 @@ module Arel
("#{locked}" unless locked.blank?)
end
- def limited_update_conditions(conditions)
+ def limited_update_conditions(conditions, taken)
+ conditions << " LIMIT #{taken}"
quoted_primary_key = engine.quote_table_name(primary_key)
"WHERE #{quoted_primary_key} IN (SELECT #{quoted_primary_key} FROM #{engine.connection.quote_table_name table.name} #{conditions})"
end
+ def add_limit_on_delete(taken)
+ "LIMIT #{taken}"
+ end
+
def supports_insert_with_returning?
false
end
diff --git a/lib/arel/engines/sql/relations/writes.rb b/lib/arel/engines/sql/relations/writes.rb
index 0a6250a..54eaee9 100644
--- a/lib/arel/engines/sql/relations/writes.rb
+++ b/lib/arel/engines/sql/relations/writes.rb
@@ -5,7 +5,7 @@ module Arel
"DELETE",
"FROM #{table_sql}",
("WHERE #{wheres.collect(&:to_sql).join(' AND ')}" unless wheres.blank? ),
- ("LIMIT #{taken}" unless taken.blank? )
+ (compiler.add_limit_on_delete(taken) unless taken.blank? )
end
end
@@ -68,9 +68,7 @@ module Arel
conditions << " ORDER BY #{order_clauses.join(', ')}" unless orders.blank?
unless taken.blank?
- conditions << " LIMIT #{taken}"
-
- conditions = compiler.limited_update_conditions(conditions)
+ conditions = compiler.limited_update_conditions(conditions,taken)
end
conditions
--
1.6.0
From 860ad2230ce658432bf62578c7d65285994e1cfa Mon Sep 17 00:00:00 2001
From: Praveen Devarao <praveen@falcon>
Date: Thu, 25 Feb 2010 14:35:16 +0530
Subject: [PATCH] raise an error if limit for deletion is specified while using IBM_DB
---
lib/arel/engines/sql/compilers/ibm_db_compiler.rb | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/lib/arel/engines/sql/compilers/ibm_db_compiler.rb b/lib/arel/engines/sql/compilers/ibm_db_compiler.rb
index e6be73d..e15e783 100644
--- a/lib/arel/engines/sql/compilers/ibm_db_compiler.rb
+++ b/lib/arel/engines/sql/compilers/ibm_db_compiler.rb
@@ -54,7 +54,7 @@ module Arel
end
def add_limit_on_delete(taken)
- "" # Limiting the number of rows to be deleted is not supported by IBM_DB
+ raise "IBM_DB does not support limit on deletion" # Limiting the number of rows to be deleted is not supported by IBM_DB
end
end
--
1.6.0
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