From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Mon, 2 Aug 2010 05:12:03 +0000 (-0400)
Subject: - The generated index name also is based on
X-Git-Tag: rel_0_6_4~65
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b2c0b50bbfa43f662afd16b7ca51bcfe17e4c351;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

- The generated index name also is based on
a "max index name length" attribute which is
separate from the "max identifier length" -
this to appease MySQL who has a max length
of 64 for index names, separate from their
overall max length of 255.  [ticket:1412]
---

diff --git a/CHANGES b/CHANGES
index 8b555f5a83..ae17630283 100644
--- a/CHANGES
+++ b/CHANGES
@@ -60,6 +60,13 @@ CHANGES
     indexes on columns with similar names still
     have unique names.  [ticket:1855]
 
+  - The generated index name also is based on 
+    a "max index name length" attribute which is
+    separate from the "max identifier length" - 
+    this to appease MySQL who has a max length
+    of 64 for index names, separate from their
+    overall max length of 255.  [ticket:1412]
+    
 - mssql
   - Fixed "default schema" query to work with
     pymssql backend.
diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index 1c61f47e18..a2d3748f33 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -1607,8 +1607,10 @@ class MySQLDialect(default.DefaultDialect):
     
     name = 'mysql'
     supports_alter = True
+    
     # identifiers are 64, however aliases can be 255...
     max_identifier_length = 255
+    max_index_name_length = 64
     
     supports_native_enum = True
     
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 0724d1fb97..390094c7de 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -59,7 +59,18 @@ class DefaultDialect(base.Dialect):
     # end Py2K
 
     name = 'default'
+    
+    # length at which to truncate
+    # any identifier.
     max_identifier_length = 9999
+    
+    # length at which to truncate
+    # the name of an index.
+    # Usually None to indicate
+    # 'use max_identifier_length'.
+    # thanks to MySQL, sigh
+    max_index_name_length = None
+    
     supports_sane_rowcount = True
     supports_sane_multi_rowcount = True
     dbapi_type_map = {}
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 0383f9690f..fcff5e3550 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -1182,8 +1182,10 @@ class DDLCompiler(engine.Compiled):
 
     def _index_identifier(self, ident):
         if isinstance(ident, sql._generated_label):
-            if len(ident) > self.dialect.max_identifier_length:
-                return ident[0:self.dialect.max_identifier_length - 8] + \
+            max = self.dialect.max_index_name_length or \
+                        self.dialect.max_identifier_length
+            if len(ident) > max:
+                return ident[0:max - 8] + \
                                 "_" + util.md5_hex(ident)[-4:]
             else:
                 return ident
diff --git a/test/dialect/test_mysql.py b/test/dialect/test_mysql.py
index 791a93c6e6..7c4cc2309f 100644
--- a/test/dialect/test_mysql.py
+++ b/test/dialect/test_mysql.py
@@ -1212,7 +1212,24 @@ class SQLTest(TestBase, AssertsCompiledSQL):
         self.assert_compile(
             select([extract('milliseconds', t.c.col1)]),
             "SELECT EXTRACT(millisecond FROM t.col1) AS anon_1 FROM t")
-
+    
+    def test_too_long_index(self):
+        exp = 'ix_zyrenian_zyme_zyzzogeton_zyzzogeton_zyrenian_zyme_zyz_5cd2'
+        tname = 'zyrenian_zyme_zyzzogeton_zyzzogeton'
+        cname = 'zyrenian_zyme_zyzzogeton_zo'
+        
+        t1 = Table(tname, MetaData(), 
+                    Column(cname, Integer, index=True),
+                )
+        ix1 = list(t1.indexes)[0]
+        
+        self.assert_compile(
+            schema.CreateIndex(ix1),
+            "CREATE INDEX %s "
+            "ON %s (%s)" % (exp, tname, cname),
+            dialect=mysql.dialect()
+        )
+        
     def test_innodb_autoincrement(self):
         t1 = Table('sometable', MetaData(), Column('assigned_id',
                    Integer(), primary_key=True, autoincrement=False),
diff --git a/test/sql/test_constraints.py b/test/sql/test_constraints.py
index 5624c0ec6d..69f29a9bd4 100644
--- a/test/sql/test_constraints.py
+++ b/test/sql/test_constraints.py
@@ -183,24 +183,30 @@ class ConstraintTest(TestBase, AssertsExecutionResults, AssertsCompiledSQL):
 
     def test_too_long_idx_name(self):
         dialect = testing.db.dialect.__class__()
-        dialect.max_identifier_length = 22
 
-        for tname, cname, exp in [
-            ('sometable', 'this_name_is_too_long', 'ix_sometable_t_09aa'),
-            ('sometable', 'this_name_alsois_long', 'ix_sometable_t_3cf1'),
-        ]:
+        for max_ident, max_index in [(22, None), (256, 22)]:
+            dialect.max_identifier_length = max_ident
+            dialect.max_index_name_length = max_index
+
+            for tname, cname, exp in [
+                ('sometable', 'this_name_is_too_long', 'ix_sometable_t_09aa'),
+                ('sometable', 'this_name_alsois_long', 'ix_sometable_t_3cf1'),
+            ]:
         
-            t1 = Table(tname, MetaData(), 
-                        Column(cname, Integer, index=True),
-                    )
-            ix1 = list(t1.indexes)[0]
+                t1 = Table(tname, MetaData(), 
+                            Column(cname, Integer, index=True),
+                        )
+                ix1 = list(t1.indexes)[0]
         
-            self.assert_compile(
-                schema.CreateIndex(ix1),
-                "CREATE INDEX %s "
-                "ON %s (%s)" % (exp, tname, cname),
-                dialect=dialect
-            )
+                self.assert_compile(
+                    schema.CreateIndex(ix1),
+                    "CREATE INDEX %s "
+                    "ON %s (%s)" % (exp, tname, cname),
+                    dialect=dialect
+                )
+        
+        dialect.max_identifier_length = 22
+        dialect.max_index_name_length = None
         
         t1 = Table('t', MetaData(), Column('c', Integer))
         assert_raises(