Merge pull request #3416 from jim-parry/userguide/db_driver_reference

User Guide - DB Driver Reference

2 files changed, 409 insertions, 1 deletions

diff --git a/user_guide_src/source/database/db_driver_reference.rst b/user_guide_src/source/database/db_driver_reference.rst
new file mode 100644
index 000000000..872077a7e
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+++ b/user_guide_src/source/database/db_driver_reference.rst
@@ -0,0 +1,407 @@
+###################
+DB Driver Reference
+###################
+
+This is the platform-independent base DB implementation class.
+This class will not be called directly. Rather, the adapter
+class for the specific database will extend and instantiate it.
+
+The how-to material for this has been split over several articles.
+This article is intended to be a reference for them.
+
+.. class:: CI_DB_driver
+
+	.. method:: initialize()
+
+		:returns:	TRUE on success, FALSE on failure
+		:rtype:	boolean
+
+		Initialize Database Settings; 
+                establish a connection to the database.
+
+	.. method:: db_pconnect()
+
+		:returns:	TRUE on success, FALSE on failure
+		:rtype:	boolean
+
+		Establish a persistent database connection
+
+	.. method:: reconnect()
+
+		:returns:	TRUE on success, FALSE on failure
+		:rtype:	boolean
+
+		Keep / reestablish the db connection if no queries have been
+                sent for a length of time exceeding the server's idle timeout.
+
+                This is only available in drivers that support it.
+
+	.. method:: db_select()
+
+		:returns:	TRUE on success, FALSE on failure
+		:rtype:	boolean
+
+		Select database
+
+	.. method:: db_set_charset($charset)
+
+		:param	string	$charset: Character set name
+		:returns:	TRUE on success, FALSE on failure
+		:rtype:	boolean
+
+		Set client character set
+
+	.. method:: platform()
+
+		:returns:	Platform name
+		:rtype:	string
+
+		The name of the platform in use (mysql, mssql, etc...)
+
+	.. method:: version()
+
+		:returns:	The version of the database being used.
+		:rtype:	string
+
+		Database version number
+
+	.. method:: query($sql[, $binds = FALSE[, $return_object = NULL]]])
+
+		:param	string	$sql: The SQL statement to execute
+		:param	array	$binds: An array of binding data
+		:param	bool	$return_object: Character set name
+		:returns:	True on "update" success, DB_result object on "query" success, FALSE on failure
+		:rtype:	mixed
+
+		Execute the query
+
+                Accepts an SQL string as input and returns a result object 
+                upon
+                successful execution of a "read" type query. Returns boolean 
+                TRUE
+                upon successful execution of a "write" type query. 
+                Returns boolean
+                FALSE upon failure, and if the $db_debug variable is set 
+                to TRUE
+                will raise an error.
+
+	.. method:: load_rdriver()
+
+		:returns:	The DB_result object appropriate for the driver in use
+		:rtype:	DB_result
+
+		Load the result drivers
+
+	.. method:: simple_query($sql)
+
+		:param	string	$sql: The SQL statement to execute
+		:returns:	True on "update" success, DB_result object on "query" success, FALSE on failure
+		:rtype:	mixed
+
+		Simple Query
+
+                This is a simplified version of the query() function. Internally
+                we only use it when running transaction commands since they do
+                not require all the features of the main query() function.
+
+	.. method:: trans_off()
+
+		:rtype:	void
+
+		Disable Transactions.
+
+                This permits transactions to be disabled at run-time.
+
+	.. method:: trans_strict([$mode = TRUE])
+
+		:param	boolean	$mode: TRUE for strict mode
+		:rtype:	void
+
+		Enable/disable Transaction Strict Mode.
+
+                When strict mode is enabled, if you are running multiple 
+                groups of
+                transactions, if one group fails all groups will be rolled back.
+                If strict mode is disabled, each group is treated autonomously, 
+                meaning
+                a failure of one group will not affect any others.
+
+	.. method:: trans_start([$test_mode = FALSE[)
+
+		:param	boolean	$test_mode: TRUE for testing mode
+		:rtype:	void
+
+		Start Transaction.
+
+	.. method:: trans_complete()
+
+		:rtype:	void
+
+		Complete Transaction.
+
+	.. method:: trans_status()
+
+                :returns:   TRUE if the transaction succeeded, FALSE if it failed
+		:rtype:	boolean
+
+		Lets you retrieve the transaction flag to determine if it
+                has failed.
+
+	.. method:: compile_binds($sql, $binds)
+
+		:param	string	$sql: The SQL statement 
+		:param	array	$binds: An array of binding data
+		:returns:	The updated SQL statement
+		:rtype:	string
+
+		Compile Bindings
+
+	.. method:: is_write_type($sql)
+
+		:param	string	$sql: The SQL statement 
+		:returns:	TRUE if the SQL statement is a "write" type of statement
+		:rtype:	boolean
+
+		Determines if a query is a "write" type.
+
+	.. method:: elapsed_time([$decimals = 6])
+
+		:param	int	$decimals: The number of decimal places
+		:returns:	The aggregate query elapsed time, in microseconds
+		:rtype:	string
+
+		Calculate the aggregate query elapsed time.
+
+	.. method:: total_queries()
+
+		:returns:	The total number of queries
+		:rtype:	int
+
+		Returns the total number of queries.
+
+	.. method:: last_query()
+
+		:returns:	The last query executed
+		:rtype:	string
+
+		Returns the last query that was executed.
+
+	.. method:: escape($str)
+
+		:param	string	$str: The string to work with
+		:returns:	The escaped string
+		:rtype:	mixed
+
+		"Smart" Escape String.
+
+                Escapes data based on type.
+                Sets boolean and null types
+
+	.. method:: escape_str($str[, $like = FALSE])
+
+		:param	mixed	$str: The string or array of strings to work with
+                :param	boolean	$like: Whether or not the string will be used in a LIKE condition
+		:returns:	The escaped string(s)
+		:rtype:	mixed
+
+		Escape String.
+
+	.. method:: escape_like_str($str)
+
+		:param	mixed	$str: The string or array of strings to work with
+                :returns:	The escaped string(s)
+		:rtype:	mixed
+
+		Escape LIKE String.
+                
+                Calls the individual driver for platform
+                specific escaping for LIKE conditions.
+
+	.. method:: primary([$table = ''])
+
+		:param	string	$table: The table name
+                :returns:	The primary key name, FALSE if none
+		:rtype:	mixed
+
+		Primary.
+                
+                Retrieves the primary key. It assumes that the row in the first
+                position is the primary key.
+
+	.. method:: count_all([$table = ''])
+
+		:param	string	$table: The table name
+                :returns:	Record count for specified table
+		:rtype:	int
+
+		"Count All" query.
+                
+                Generates a platform-specific query string that counts 
+                all records in
+                the specified database.
+
+	.. method:: list_tables([$constrain_by_prefix = FALSE])
+
+		:param	boolean	$constrain_by_prefix: TRUE to constrain the tables considered
+                :returns:	Array of table names, FALSE if the operation is unsupported
+		:rtype:	mixed
+
+		Returns an array of table names.
+
+	.. method:: table_exists($table_name)
+
+		:param	string	$table_name: The table name
+                :returns:	TRUE if that table exists
+		:rtype:	boolean
+
+		Determine if a particular table exists.
+
+	.. method:: list_fields([$table = ''])
+
+		:param	string	$table: The table name
+                :returns:	Array of field names, FALSE if the table doesn't exist or the operation is un-supported
+		:rtype:	mixed
+
+		Fetch Field Names.
+
+	.. method:: field_exists($field_name, $table_name)
+
+		:param	string	$table_name: The table name
+                :param	string	$field_name: The field name
+                :returns:	TRUE if that field exists in that table
+		:rtype:	boolean
+
+		Determine if a particular field exists.
+
+	.. method:: field_data([$table = ''])
+
+		:param	string	$table: The table name
+                :returns:	Object with field data, FALSE if no table given
+		:rtype:	mixed
+
+		Returns an object with field data.
+
+	.. method:: escape_identifiers($item)
+
+		:param	mixed	$item: The item or array of items to escape
+                :returns:	The item(s), escaped
+		:rtype:	mixed
+
+		Escape the SQL Identifiers.
+                
+                This function escapes column and table names
+
+	.. method:: insert_string($table, $data)
+
+		:param	string	$table: The table upon which the query will be performed
+                :param	array	$data: an associative array of data key/values
+                :returns:	The SQL insert string
+		:rtype:	string
+
+		Generate an insert string.
+
+	.. method:: update_string($table, $data, $where)
+
+		:param	string	$table: The table upon which the query will be performed
+                :param	array	$data: an associative array of data key/values
+                :param	mixed	$where: the "where" statement
+                :returns:	The SQL update string
+		:rtype:	string
+
+		Generate an update string.
+
+	.. method:: call_function($function)
+
+		:param	string	$function: Function name
+                :returns:	The function result
+		:rtype:	string
+
+		Enables a native PHP function to be run, using a platform 
+                agnostic wrapper.
+
+	.. method:: cache_set_path([$path = ''])
+
+		:param	string	$path: the path to the cache directory
+                :rtype:	void
+
+		Set Cache Directory Path.
+
+	.. method:: cache_on()
+
+                :returns:	cache_on value
+                :rtype:	boolean
+
+		Enable Query Caching.
+
+	.. method:: cache_off()
+
+                :returns:	cache_on value
+                :rtype:	boolean
+
+		Disable Query Caching.
+
+	.. method:: cache_delete([$segment_one = ''[, $segment_two = '']])
+
+                :param	string	$segment_one: first URI segment
+                :param	string	$segment_two: second URI segment
+                :returns:	TRUE on success, FALSE on failure
+                :rtype:	boolean
+
+		Delete the cache files associated with a particular URI
+
+	.. method:: cache_delete_all()
+
+                :returns:	TRUE on success, FALSE on failure
+                :rtype:	boolean
+
+		Delete All cache files
+
+	.. method:: close()
+
+                :rtype:	void
+
+		Close DB Connection
+
+	.. method:: display_error([$error = ''[, $swap = ''[, $native = FALSE]]])
+
+                :param	string	$error: the error message
+                :param	string	$swap: any "swap" values
+                :param	boolean	$native: whether to localize the message
+                :returns:   sends the application/views/errors/error_db.php template
+                :rtype:	string
+
+		Display an error message
+
+	.. method:: protect_identifiers($item[, $prefix_single = FALSE[, $protect_identifiers = NULL[, $field_exists = TRUE]]])
+
+                :param	string	$item: the item
+                :param	boolean	$prefix_single: whether to use a single prefix
+                :param	boolean	$protect_identifiers: whether to protect identifiers
+                :param	boolean	$field_exists: whether the supplied item does not contain a field name.
+                :returns:   the modified item
+                :rtype:	string
+
+		Protect Identifiers.
+                
+                This function is used extensively by the Query Builder class, 
+                and by
+                a couple functions in this class.
+                It takes a column or table name (optionally with an alias) 
+                and inserts
+                the table prefix onto it. Some logic is necessary in order 
+                to deal with
+                column names that include the path. Consider a query like this::
+                
+                        SELECT * FROM hostname.database.table.column AS c FROM hostname.database.table
+                
+                Or a query with aliasing::
+                
+                        SELECT m.member_id, m.member_name FROM members AS m
+                
+                Since the column name can include up to four segments 
+                (host, DB, table, column)
+                or also have an alias prefix, we need to do a bit of work 
+                to figure this out and
+                insert the table prefix (if it exists) in the proper position, 
+                and escape only
+                the correct identifiers.
\ No newline at end of file
diff --git a/user_guide_src/source/database/index.rst b/user_guide_src/source/database/index.rst
index 4612daf9d..2fb50f9be 100644
--- a/user_guide_src/source/database/index.rst
+++ b/user_guide_src/source/database/index.rst
@@ -21,4 +21,5 @@ patterns. The database functions offer clear, simple syntax.
 	Custom Function Calls <call_function>
 	Query Caching <caching>
 	Database Manipulation with Database Forge <forge>
-	Database Utilities Class <utilities>
\ No newline at end of file
+	Database Utilities Class <utilities>
+	Database Driver Reference <db_driver_reference>
\ No newline at end of file