diff --git a/tutorial/tutorial.wmml b/tutorial/tutorial.wmml
index f1b71ef4ee90e7892a536a69db2f65e3d503a00a..6318e19f257e0682942fa950022fd31f6aaaa642 100644
--- a/tutorial/tutorial.wmml
+++ b/tutorial/tutorial.wmml
@@ -7665,7 +7665,8 @@ write(.Table.ASCII.encode(t->select("frukt")->distinct("frukt")->
<hr noshade size=1>
<module name=Yabu>
-<section title="Yabu">
+<section title="Yabu transaction database">
+
Yabu is a all purpose database, used to store data records associated with a
unique key. Yabu is very similar to mappings, however, records are
stored in files and not in memory. Also, Yabu features <i>tables</i>,
@@ -7674,14 +7675,142 @@ database. A characteristic feature of Yabu is that it allows for
<i>transactions</i>. A transaction is a sequence of database commands
that will be accepted in whole, or not at all.<p>
-Some effort have been made to make sure that Yabu is crash safe.
+Some effort has been made to make sure that Yabu is crash safe.
This means that the database should survive process kills, core
-dumps and such -- although this is not something that can absolutely
+dumps and such -- although this is not something that can be absolutely
guaranteed. Also, all non-commited and pending transactions will
be cancelled in case of a crash.<p>
+Yabu uses three types of objects, listed below:<p>
+
+<ul>
+<li>The <i>db</i> object is the main database object. It can create
+ table objects. The methods available in the db object are:
+ <link to=Yabu.db.table><tt>table</tt></link> (the <tt>[]</tt> operator),
+ <link to=Yabu.db.list_tables><tt>list_tables</tt></link>
+ (<tt>indices</tt>),
+ <link to=Yabu.db.sync><tt>sync</tt></link> and
+ <link to=Yabu.db.purge><tt>purge</tt></link>.
+<li>The <i>table</i> object handles tables. It is used in order to
+ store and fetch records from the database. It can create transaction
+ objects. The methods available in the table object are:
+ <link to=Yabu.table.set><tt>set</tt></link> (the <tt>[]=</tt> operator),
+ <link to=Yabu.table.get><tt>get</tt></link> (the <tt>[]</tt> operator),
+ <link to=Yabu.table.list_keys><tt>list_keys</tt></link> (<tt>indices</tt>),
+ <link to=Yabu.table.delete><tt>delete</tt></link>,
+ <link to=Yabu.table.transaction<tt>transaction</tt></link> and
+ <link to=Yabu.table.purge><tt>purge</tt></link>.
+<li>The <i>transaction</i> object handles transactions. It works
+ like the table object. The difference is that a sequence of commands
+ must end with <tt>commit</tt> or <tt>rollback</tt>. The methods available
+ in the table object are:
+ <link to=Yabu.table.set><tt>set</tt></link> (the <tt>[]=</tt> operator),
+ <link to=Yabu.table.get><tt>get</tt></link> (the <tt>[]</tt> operator),
+ <link to=Yabu.table.list_keys><tt>list_keys</tt></link> (<tt>indices</tt>),
+ <link to=Yabu.table.delete><tt>delete</tt></link>,
+ <link to=Yabu.transaction.commit><tt>commit</tt></link> and
+ <link to=Yabu.transaction.rollback><tt>rollback</tt></link>.
+</ul><p>
+
+A Yabu database can operate in two basic modes:<p>
+
+<ul>
+<li> Read mode. In read mode, nothing in the database can be altered,
+ added nor deleted. All Yabu files will be opended in read mode, which
+ means that the database will be in the same state on the disk as it
+ was prior to the opening.
+<li> Write mode. In write mode, records can be altered, added or deleted. In
+ combination with create mode, new tables can also be added. Transactions
+ can optionally be used with write mode. When compressed mode is enabled,
+ all records will be compressed before stored on to disk.
+</ul>
+
+Compressed databases opened without compress mode enabled will be handled
+correctly in both modes, provided that the Gz module is available.
+However, new records will no longer be compressed in write mode.<p>
+
+Transactions make it possible to alter, add or delete several database
+records and guarantee that all changes, or no changes, will be accepted
+by the database. A transaction object is basically a table object with
+a few restrictions and additions, listed below:<p>
+
+<ul>
+<li>Purge is not available in a transaction object.
+<li>Commit. In order to make all changes take affect, commit must be
+ issued at the end of a transaction sequence. Changes done in a
+ transaction object will <i>never</i> take affect before commit,
+ even if the database is shut down, the program crashes etc.
+<li>Rollback. A rollback cancels all changes made by the transaction object.
+</ul><p>
+
+Rollbacks always succeeds. However, with commit that is not always
+the case. A commit will fail if:<p>
+
+<ul>
+<li>A record that is altered by the transaction object is altered
+ again by something else, before commit. This is called a conflict,
+ and will result in an error upon commit.
+</ul><p>
+
+A simple example is illustrated below.<p>
+
+<man_example>
+<example language=pike>
+
+// Create a database called "my.database" in write/create mode.
+object db = Yabu.db("my.database", "wc");
+
+// Create a table called "fruit".
+object table = db["fruit"];
+
+// Store a record called "orange" with the value "yummy".
+table["orange"] = "yummy";
+
+// Store a record called "apple" with the value 42.
+table["apple"] = 42;
+</example>
+</man_example><p>
+
+Transactions are slightly more complex, but not much so. See example
+below.
+
+<man_example>
+<example language=pike>
+
+// Create a database called "my.database"
+// in write/create/transaction mode.
+object db = Yabu.db("my.database", "wct");
+
+// Create a table called "fruit".
+object table = db["fruit"];
+
+// Create a transaction object for table "fruit".
+object transaction = table->transaction();
+
+// Store a record called "orange" with
+// the value "yummy". Note that this record
+// is only visible through the transaction object.
+transaction["orange"] = "yummy";
+
+// Store a record called "apple" with the value 42.
+// As with "orange", this record is invisible
+// for all objects except this transaction object.
+transaction["apple"] = 42;
+
+// Commit the records "orange" and "apple".
+// These records are now a part of the database.
+transaction->commit();
+
+</example>
+</man_example>
+
<hr noshade size=1>
+<section title="The db object">
+
+The db object is used to open a Yabu database. The db object
+creates table objects.<p>
+
<method name=Yabu.db->create title="Open a Yabu database">
<man_syntax>
void create(string <i>directory</i>, string <i>mode</i>);
@@ -7717,8 +7846,8 @@ weather a database is already open or not.
<man_example>
<example language=pike>
-// Open a database in create/write mode.
-object db = Yabu.db("my.database", "cw");
+// Open a database in create/write/transaction mode.
+object db = Yabu.db("my.database", "cwt");
// Open a database in read mode.
object db = Yabu.db("my.database", "r");
@@ -7730,9 +7859,7 @@ object db = Yabu.db("my.database", "cwC");
<man_see>
Yabu.db->table,
-Yabu.db->`[],
Yabu.db->list_tables,
-Yabu.db->_indices,
Yabu.db->sync,
Yabu.db->purge
</man_see>
@@ -7744,6 +7871,7 @@ Yabu.db->purge
<method name=Yabu.db->table title="Open a table">
<man_syntax>
object(table) table(string <i>table_name</i>);<br>
+object(table) `[](string <i>table_name</i>);<br>
</man_syntax>
<man_description>
This method opens a table with <i>table_name</i>. If the table
@@ -7751,29 +7879,7 @@ does not exist, it will be created. A table object will be returned.
</man_description>
<man_see>
-Yabu.db->`[],
-Yabu.db->list_tables,
-Yabu.db->_indices,
-Yabu.db->sync,
-Yabu.db->purge
-</man_see>
-
-</method>
-
-<hr noshade size=1>
-
-<method name=Yabu.db->`[] title="Open a table">
-<man_syntax>
-object(table) `[](string <i>table_name</i>);<br>
-</man_syntax>
-<man_description>
-Synonymous with <link to=Yabu.db.table>Yabu.table->table</link>.
-</man_description>
-
-<man_see>
-Yabu.db->table,
Yabu.db->list_tables,
-Yabu.db->_indices,
Yabu.db->sync,
Yabu.db->purge
</man_see>
@@ -7785,35 +7891,14 @@ Yabu.db->purge
<method name=Yabu.db->list_tables title="List all tables">
<man_syntax>
array(string) list_tables();<br>
-</man_syntax>
-<man_description>
-This method lists all available tables.
-</man_description>
-
-<man_see>
-Yabu.db->table,
-Yabu.db->`[],
-Yabu.db->_indices,
-Yabu.db->sync,
-Yabu.db->purge
-</man_see>
-
-</method>
-
-<hr noshade size=1>
-
-<method name=Yabu.db->_indices title="List all tables">
-<man_syntax>
array(string) _indices();<br>
</man_syntax>
<man_description>
-Synonymous with <link to=Yabu.table.set>Yabu.table->list_tables</link>.
+This method lists all available tables.
</man_description>
<man_see>
Yabu.db->table,
-Yabu.db->`[],
-Yabu.db->list_tables,
Yabu.db->sync,
Yabu.db->purge
</man_see>
@@ -7835,9 +7920,7 @@ information in memory.
<man_see>
Yabu.db->table,
-Yabu.db->`[],
Yabu.db->list_tables,
-Yabu.db->_indices,
Yabu.db->purge
</man_see>
@@ -7855,19 +7938,26 @@ This method deletes the whole database and all database files stored on disk.
<man_see>
Yabu.db->table,
-Yabu.db->`[],
Yabu.db->list_tables,
-Yabu.db->_indices,
Yabu.db->sync
</man_see>
</method>
+</section>
+
<hr noshade size=1>
+<section title="The table object">
+
+The table object is used to store and retrieve information from
+a table. Table objects are created by the db class. A table object
+can create a transaction object.
+
<method name=Yabu.table->set title="Store a record in a table">
<man_syntax>
mixed set(string key, mixed data);<br>
+mixed `[]=(string key, mixed data);<br>
</man_syntax>
<man_description>
This method stores the contents of <i>data</i> as a record with the name
@@ -7878,24 +7968,8 @@ replaced. Records can only be added to the database in write mode.
<man_see>
Yabu.table->get,
Yabu.table->delete,
-Yabu.table->list_keys
-</man_see>
-
-</method>
-<hr noshade size=1>
-
-<method name=Yabu.table->`[]= title="Store a record in a table">
-<man_syntax>
-mixed `[]=(string key, mixed data);<br>
-</man_syntax>
-<man_description>
-Synonymous with <link to=Yabu.table.set>Yabu.table->set</link>.
-</man_description>
-
-<man_see>
-Yabu.table->get,
-Yabu.table->delete,
-Yabu.table->list_keys
+Yabu.table->list_keys,
+Yabu.table->purge
</man_see>
</method>
@@ -7905,6 +7979,7 @@ Yabu.table->list_keys
<method name=Yabu.table->get title="Fetch a record from a table">
<man_syntax>
mixed get(string key);<br>
+mixed `[](string key);<br>
</man_syntax>
<man_description>
This method fetches the data associated with the record name
@@ -7914,25 +7989,8 @@ This method fetches the data associated with the record name
<man_see>
Yabu.table->set,
Yabu.table->delete,
-Yabu.table->list_keys
-</man_see>
-
-</method>
-
-<hr noshade size=1>
-
-<method name=Yabu.table->`[] title="Fetch a record from a table">
-<man_syntax>
-mixed `[](string key);<br>
-</man_syntax>
-<man_description>
-Synonymous with <link to=Yabu.table.get>Yabu.table->get</link>.
-</man_description>
-
-<man_see>
-Yabu.table->set,
-Yabu.table->delete,
-Yabu.table->list_keys
+Yabu.table->list_keys,
+Yabu.table->purge
</man_see>
</method>
@@ -7942,33 +8000,17 @@ Yabu.table->list_keys
<method name=Yabu.table->list_keys title="List the records in a table">
<man_syntax>
array(string) list_keys();<br>
-</man_syntax>
-<man_description>
-This method lists all record names in the table.
-</man_description>
-
-<man_see>
-Yabu.table->set,
-Yabu.table->get,
-Yabu.table->delete
-</man_see>
-
-</method>
-
-<hr noshade size=1>
-
-<method name=Yabu.table->_indices title="List the records in a table">
-<man_syntax>
array(string) _indices();<br>
</man_syntax>
<man_description>
-Synonymous with <link to=Yabu.table.get>Yabu.table->list_keys</link>.
+This method lists all record names in the table.
</man_description>
<man_see>
Yabu.table->set,
Yabu.table->get,
-Yabu.table->delete
+Yabu.table->delete,
+Yabu.table->purge
</man_see>
</method>
@@ -7986,7 +8028,8 @@ This method deletes the record with the name <i>key</i>.
<man_see>
Yabu.table->set,
Yabu.table->get,
-Yabu.table->list_keys
+Yabu.table->list_keys,
+Yabu.table->purge
</man_see>
</method>
@@ -8000,6 +8043,14 @@ void purge();<br>
<man_description>
This method deletes the whole table and the table files on disk.
</man_description>
+
+<man_see>
+Yabu.table->set,
+Yabu.table->get,
+Yabu.table->list_keys,
+Yabu.table->delete
+</man_see>
+
</method>
<hr noshade size=1>
@@ -8012,14 +8063,7 @@ object(transaction) transaction();<br>
A transaction is a sequence of table commands that will be accepted in
whole, or not at all. If the program for some reason crashes or makes
an abrupt exit during a transaction, the transaction is cancelled.<p>
-This method returns a transaction object. It can be used in the same
-way as a table object. The difference is that in order to make the
-changes take affect, <link to=Yabu.transaction.commit>commit</link>
-must be issued. Before that, all changes will be local to the
-transaction object. Also, if a record in a transaction is altered
-before the transaction is commited, a conflict will arise upon commit.
-A transaction can be cancelled using <link to=Yabu.transaction.rollback>
-rollback</link>.
+This method returns a transaction object.
</man_description>
<man_see>
@@ -8029,8 +8073,22 @@ Yabu.transaction->rollback
</method>
+</section>
+
<hr noshade size=1>
+<section title="The transaction object">
+
+The transaction object handles transactions. Transaction objects
+are created by the table object. A transaction object can be used
+in the same way as a table object. The difference is that in order
+to make the changes take affect, <link to=Yabu.transaction.commit>
+commit</link> must be issued. Before that, all changes will be local to
+the transaction object. Also, if a record in a transaction is altered
+before the transaction is commited, a conflict will arise upon commit.
+A transaction can be cancelled using <link to=Yabu.transaction.rollback>
+rollback</link>.
+
<method name=Yabu.transaction->commit title="Commit a transaction">
<man_syntax>
void commit();<br>
@@ -8066,6 +8124,8 @@ Yabu.transaction->commit
</method>
+</section>
+
</section>
</module>