t/50fork.t made a little more resilient

[dbsrgits/DBIx-Class-Historic.git] / lib / DBIx / Class / Manual / Cookbook.pod

diff --git a/lib/DBIx/Class/Manual/Cookbook.pod b/lib/DBIx/Class/Manual/Cookbook.pod
index ec8948e..1ab0e31 100644 (file)
--- a/lib/DBIx/Class/Manual/Cookbook.pod
+++ b/lib/DBIx/Class/Manual/Cookbook.pod
@@ -231,8 +231,7 @@ main query. Five CDs, five extra queries. A hundred CDs, one hundred extra
 queries!
 
 Thankfully, L<DBIx::Class> has a C<prefetch> attribute to solve this problem.
-This allows you to fetch results from a related table as well as the main table
-for your class:
+This allows you to fetch results from related tables in advance:
 
   my $rs = $schema->resultset('CD')->search(
     {
@@ -325,6 +324,31 @@ notes:
   # WHERE liner_notes.notes LIKE '%some text%'
   # AND author.name = 'A. Writer'
 
+=head2 Multi-step prefetch
+
+From 0.04999_05 onwards, C<prefetch> can be nested more than one relationship
+deep using the same syntax as a multi-step join:
+
+  my $rs = $schema->resultset('Tag')->search(
+    {},
+    {
+      prefetch => {
+        cd => 'artist'
+      }
+    }
+  );
+
+  # Equivalent SQL:
+  # SELECT tag.*, cd.*, artist.* FROM tag
+  # JOIN cd ON tag.cd = cd.cdid
+  # JOIN artist ON cd.artist = artist.artistid
+
+Now accessing our C<cd> and C<artist> relationships does not need additional
+SQL statements:
+
+  my $tag = $rs->first;
+  print $tag->cd->artist->name;
+
 =head2 Transactions
 
 As of version 0.04001, there is improved transaction support in
@@ -415,7 +439,7 @@ development, you might like to put the following signal handler in
 your main database class to make sure it disconnects cleanly:
 
   $SIG{INT} = sub {
-    __PACKAGE__->storage->dbh->disconnect;
+    __PACKAGE__->storage->disconnect;
   };
 
 =head2 Schema import/export
@@ -481,11 +505,29 @@ namespace, which is currently left as an excercise for the reader.
 The following example shows simplistically how you might use DBIx::Class to
 deploy versioned schemas to your customers. The basic process is as follows:
 
-1) Create a DBIx::Class schema
-2) Save the schema
-3) Deploy to customers
-4) Modify schema to change functionality
-5) Deploy update to customers
+=over 4
+
+=item 1.
+
+Create a DBIx::Class schema
+
+=item 2.
+
+Save the schema
+
+=item 3.
+
+Deploy to customers
+
+=item 4.
+
+Modify schema to change functionality
+
+=item 5.
+
+Deploy update to customers
+
+=back
 
 =head3 Create a DBIx::Class schema
 
@@ -513,10 +555,19 @@ script suitable for each. To support PostgreSQL too:
 There are several ways you could deploy your schema. These are probably
 beyond the scope of this recipe, but might include:
 
-1) Require customer to apply manually using their RDBMS.
-2) Package along with your app, making database dump/schema update/tests
+=over 4
+
+=item 1.
+
+Require customer to apply manually using their RDBMS.
+
+=item 2.
+
+Package along with your app, making database dump/schema update/tests
 all part of your install.
 
+=back
+
 =head3 Modify the schema to change functionality
 
 As your application evolves, it may be necessary to modify your schema to
@@ -536,4 +587,34 @@ database schema:
 
 The schema update can be deployed to customers using the same method as before.
 
+=head2 Setting limit dialect for SQL::Abstract::Limit
+
+In some cases, SQL::Abstract::Limit cannot determine the dialect of the remote
+SQL-server by looking at the database-handle. This is a common problem when
+using the DBD::JDBC, since the DBD-driver only know that in has a Java-driver
+available, not which JDBC-driver the Java component has loaded.
+This specifically sets the limit_dialect to Microsoft SQL-server (Se more names
+in SQL::Abstract::Limit -documentation.
+
+  __PACKAGE__->storage->sql_maker->limit_dialect('mssql');
+
+The JDBC-bridge is one way of getting access to a MSSQL-server from a platform
+that Microsoft doesn't deliver native client libraries for. (e.g. Linux)
+
+=head2 Setting quotes for the generated SQL. 
+
+If the database contains columnames with spaces and/or reserved words, the
+SQL-query needs to be quoted. This is done using:
+
+  __PACKAGE__->storage->sql_maker->quote_char([ qw/[ ]/] );
+  __PACKAGE__->storage->sql_maker->name_sep('.');
+
+The first sets the quotesymbols. If the quote i "symmetric" as " or '
+  
+  __PACKAGE__->storage->sql_maker->quote_char('"');
+
+is enough. If the left qoute differs form the right quote, the first 
+notation should be used. name_sep needs to be set to allow the 
+SQL generator to put the quotes the correct place. 
+
 =cut