$smcFunc: Difference between revisions

The following applies only to version 2.0

In SMF 2.0, multiple database support was introduced. This was implemented by developers as a new layer of database functions along with a new security model, which provides a fast and secure method to work across database systems.

Below is a list of the database functions that currently exist in 2.0. Each of these links will direct you towards a section about that function that will help you understand what each one does, how its input is expected and if possible, the exact duplicate function for mysql. An example is provided as well for most of these, these examples come straight from the SMF Source code.

Please note our Function Database now has the latest SMF 2.0 functions for your information and may help in explaining the functions. They do not use the $smcFunc variables that this guide does. For most of your functions you will see "smf_db_xxx" where xxx is the function name such as "smf_db_insert" that is used by $smcFunc['db_insert'].

Database Functions

db_query

Usage $smcFunc['db_query'] (identifier, query, values, connection)

Works Similar to how db_query worked in 1.x versions.
Identifier is used for identifying specific queries that will be handled specially.
Values is an array of values you are intending to use in the query.

Example

            $result = $smcFunc['db_query'](''', '
                SELECT poster_time
                FROM {db_prefix}messages
                WHERE id_msg = {int:id_msg}
                LIMIT 1',
                array(
                    'id_msg' => $user_settings['id_msg_last_visit'],
                )
            );

db_quote

Usage $smcFunc['db_quote'] (query, values, connection)

Works Similar to how db_query works with the exception of no identifier.
Values is an array of values you are intending to use in the query.
Does not execute the query, Formats as if it where going to be and returns the string.

Example

            $realNameMatches[] = $smcFunc['db_quote'](
                '{string:possible_user}', 
                array(
                    'possible_user' => $possible_user
                )
            );

db_fetch_assoc

Usage $smcFunc['db_fetch_assoc'] ($result)

Will return exact same results as <a href="http://php.net/mysql_fetch_assoc" class="bbc_link" target="_blank">mysql_fetch_assoc</a>

Example

        while ($row = $smcFunc['db_fetch_assoc']($request))
            $search_params['brd'][] = $row['id_board'];

db_fetch_row

Usage $smcFunc['db_fetch_row'] ($result)

Will return exact same results as <a href="http://php.net/mysql_fetch_row" class="bbc_link" target="_blank">mysql_fetch_row</a>.
Emulated while using SQlite with smf_sqlite_fetch_row.

Example

        while ($row = $smcFunc['db_fetch_row']($request))
            $toDelete[] = $row[0];

db_free_result

Usage $smcFunc['db_free_result'] ($result)

Will return exact same results as <a href="http://php.net/mysql_free_result" class="bbc_link" target="_blank">mysql_free_result</a>.
Emulated while using SQlite with smf_sqlite_free_result.

Example

        $smcFunc['db_free_result']($request);

db_insert

Usage $smcFunc['db_insert'] (method, table, columns, data, keys, disable_trans, connection)

Emulated with smf_db_insert.
Method tells how to change the data. Accepts "replace" "ignore" or "insert".
Table: the data will be changed on.
Columns: An array ( column_name => input_type) set that holds all column names that will be changed and their expected input type.
Data holds an array that must be as long as the column array with all the data that will be used.
Keys is supposed to hold the tables key information, only appears to affect sqlite and postrgresql (when using "replace") versions.

Example

        $smcFunc['db_insert']('replace',
            '{db_prefix}log_topics',
            array(
                'id_member' => 'int', 'id_topic' => 'int', 'id_msg' => 'int',
            ),
            array(
                $user_info['id'], $topic, $modSettings['maxMsgID'],
            ),
            array('id_member', 'id_topic')
        );

db_insert_id

Usage $smcFunc['db_insert_id'] (table, field, connect)

Will return exact same results as <a href="http://php.net/mysql_insert_id" class="bbc_link" target="_blank">mysql_insert_id</a>.
Emulated while using PostgreSQL with smf_db_insert_id.
Table holds the table name that was affected.
Field holds the name of the field that was affected.

Example

        $bcinfo['id_poll'] = $smcFunc['db_insert_id']('{db_prefixpolls', 'id_poll');

db_num_rows

Usage $smcFunc['db_num_rows'] ($result)

Will return exact same results as <a href="http://php.net/mysql_num_rows" class="bbc_link" target="_blank">mysql_num_rows</a>.

Example

    if ($smcFunc['db_num_rows']($request) == 0)
        fatal_lang_error('admin_file_not_found', true, array($_REQUEST['filename']));

db_data_seek

Usage $smcFunc['db_data_seek'] ($result, row_number)

Will return exact same results as <a href="http://php.net/mysql_data_seek" class="bbc_link" target="_blank">mysql_data_seek</a>.
Emulated while using PostgreSQL with db_data_seek.
Row_number is the row number you wish the pointer to be at.

Example

    // Start from the beginning...
    if ($reset)
        return @$smcFunc['db_data_seek']($messages_request, 0);

db_num_fields

Usage $smcFunc['db_num_fields'] ($result)

Will return exact same results as <a href="http://php.net/mysql_num_fields" class="bbc_link" target="_blank">mysql_num_fields</a>.

Example

        // Get the fields in this row...
        $field_list = array();
        for ($j = 0; $j < $smcFunc['db_num_fields']($result); $j++)
        {
            // Try to figure out the type of each field. (NULL, number, or 'string'.)
            if (!isset($row[$j]))
                $field_list[] = 'NULL';
            elseif (is_numeric($row[$j]))
                $field_list[] = $row[$j];
            else
                $field_list[] = ''' . $smcFunc['db_escape_string']($row[$j]) . ''';
        }

db_escape_string

Usage $smcFunc['db_escape_string'] (uncleaned_string)

MySQL databases use addslashes function instead of <a href="http://php.net/mysql_escape_string" class="bbc_link" target="_blank">mysql_escape_string</a>.
Does not require a database connection to use this.

Example

    // Add slashes to every element, even the indexes!
    foreach ($var as $k => $v)
        $new_var[$smcFunc['db_escape_string']($k)] = escapestring__recursive($v);

db_unescape_string

Usage $smcFunc['db_unescape_string'] (cleaned_string)

MySQL databases use stripslashes function.
PostgreSQL databases will emulate this with smf_postg_unescape_string.
SQlite databases will emulate this with smf_sqlite_unescape_string.
Does not require a database connection to use this.

Example

    // Strip the slashes from every element.
    foreach ($var as $k => $v)
        $new_var[$smcFunc['db_unescape_string']($k)] = unescapestring__recursive($v);

db_server_info

Usage $smcFunc['db_server_info'] (connection)

Attempts to get database server information.

Example

        // Some MySQL versions are superior to others.
        $this->canDoBooleanSearch = version_compare($smcFunc['db_server_info']($db_connection), '4.0.1', '>=') == 1;

db_tablename

Usage $smcFunc['db_tablename'] ($result, table_number)

Will return exact same results as <a href="http://php.net/mysql_tablename" class="bbc_link" target="_blank">mysql_tablename</a>.
Finds a table by a number.
Does not appear to be used in SMF coding yet.

No example provided

db_affected_rows

Usage $smcFunc['db_affected_rows'] (connection)

Will return exact same results as <a href="http://php.net/mysql_affected_rows" class="bbc_link" target="_blank">mysql_affected_rows</a>.

Example

        if ($smcFunc['db_affected_rows']() <= 0)
        {
            loadLanguage('Admin');
            fatal_lang_error('salvaged_category_error', false);
        }

db_transaction

Usage $smcFunc['db_transaction'] (type, connection)

Same as calling mysql queries for "BEGIN", "ROLLBACK", and "COMMIT".
Accepts "begin", "rollback", and "commit".

Example

    $smcFunc['db_transaction']('begin');
    // Do the table and indexes...
    $smcFunc['db_query'](''', $table_query,
        'security_override'
    );
    foreach ($index_queries as $query)
        $smcFunc['db_query'](''', $query,
        'security_override'
    );

    $smcFunc['db_transaction']('commit');

db_error

Usage $smcFunc['db_error'] (connection)

Will return the exact same results as mysql_error.
SQlite databases will emulate this with smf_sqlite_last_error, and the connection is ignored.

Example

            // Language files aren't loaded yet.
            $db_error = @$smcFunc['db_error']($db_connection);
            @mail($webmaster_email, $mbname . ': SMF Database Error!', 'There has been a problem with the database!' . ($db_error == ''' ? ''' : "" . $smcFunc['db_title'] . ' reported:' . "" . $db_error) . "" . 'This is a notice email to let you know that SMF could not connect to the database, contact your host if this continues.');

db_select_db

Usage $smcFunc['db_select_db'] (database_name, connection)

Will return exact same results as mysql_select_db.
PostgreSQL functions will have this return true always in postg_select_db. PostgreSQL has database selected upon creating the connection.
SQlite will do nothing as there is only one database per file.

No Examples

db_title

Usage $smcFunc['db_title'] ()

Name of the database being used. Such as MySQL, PostgreSQL and SQlite.
Should not be called as a function, but used a string.

No Examples

db_sybase

Usage $smcFunc['db_sybase'] ()

Tells SMF whether the Database uses sybase or not.
PostgreSQL and SQlite use sybase, MySQL does not.

No Examples

db_case_sensitive

Usage $smcFunc['db_case_sensitive'] ()

Tells SMF whether the Database is case sensitive or not.
PostgreSQL is case sensitive, MySQL and SQlite are not.

No Examples

Database Package Functions only.

The below functions only exist when using db_extend('packages');

db_add_column

Usage $smcFunc['db_add_column'] (string $table_name, array $column_info, array $parameters, string $if_exists, string $error)

This function allows for adding a column to a table.

Parameters

table_name
- an already existing table.
column_info
- an array of data containing with keys
  - string 'name' of the column
  - string 'type' of the column
  - int 'size' of the column if required by type.
  - bool 'null', whether to use "null" or "not null"
  - string/int 'default' should contain the default value for the column
  - bool' auto' tells whether the column uses auto_increment or not.
  - bool 'unsigned' (true/false) specifies whether the column is unsigned or not.
parameters
- deprecated as of 2.0 RC3, leave empty
if_exists
- controls what to do if the column exists
  - 'update' - updates the column
error
- what to do if an error was encountered
  - fatal - Default

Returns bool true if column added (changed); false otherwise

db_add_index

Usage $smcFunc['db_add_index'] (table_name, index_into, parameters, if_exists, error)

This function allows for adding an index to a table.

Parameters

table_name - an already existing table
index_info - an array of data as follows:
- - string 'type' - index type. Can be one of 'primary', 'unique', or 'index'. Leave this entry out to keep a regular index.
  - string 'name' - name of index, can be left blank to use first column name.
  - 'array 'columns' - column names
parameters
- none, leave empty
if_exists
- controls what to do if the index exists
  - 'update' - updates the index but overwrites if primary
error
- what to do if an error was encountered
  - fatal - Default

Returns bool false if no columns specified

db_calculate_type

Usage $smcFunc['db_calculate_type'] (type_name, type_size, reverse)

This function will calculate the type and size for a column.

Parameters

type_name should be the type of the column.
type_size contains the size of the column (can be empty
reverse whether or not to reverse things

Returns array the first value is the type, and the second value is the size

db_change_column

Usage $smcFunc['db_change_column'] (table_name, old_column, column_info, parameters, error)

with db_extend('packages');
This function allows for changing an existing column structure.
'table name' should be an already existing table. If you specific a database prefix, add 'no_prefix' to the paramaters.
'old_column' should be an already existing column name.

'column_info' should be an array of data containing with keys* 'name' of the column

'type' of the column
'size' of the column if required by type.
'null', whether to use "null" or "not null"
'default' should contain the default value for the column
'auto' tells whether the column uses auto_increment or not.
As of 2.0 RC2, 'unsigned' (true/false) specifies whether the column is unsigned or not.
Parameters contains special items such in an array such as 'no_prefix' to not auto add a the database prefix.

db_create_table

Usage $smcFunc['db_create_table'] (table_name, columns, indexes, parameters, if_exists, error)

with db_extend('packages');
This function allows for creating a table. You can not create a SMF default table.
Table_name can have a database prefix. If you specific a database prefix, add 'no_prefix' to the paramaters.
columns is a multi-dimensional array containing the columns to be in the table. This is passed to $smcFunc['db_add_column'] function for handling.
if_exists is by default using "update". Other options are 'overwrite', 'ignore', 'error', 'update_remove',
Parameters contains special items such in an array such as 'no_prefix' to not auto add a the database prefix.
if_exists controls what to do if the column exists, by default it updates the column

db_drop_table

Usage $smcFunc['db_drop_table'] (table_name, parameters, error)

with db_extend('packages');
This function allows for removal a table. You can not delete a SMF default table.
Table_name can have a database prefix. If you specific a database prefix, add 'no_prefix' to the parameters.
Parameters contains special items such in an array such as 'no_prefix' to not auto add a the database prefix.

db_table_structure

Usage $smcFunc['db_table_structure'] (table_name)

with db_extend('packages');
This function returns the structure of a table.
If you need to specific the database prefix use {db_prefix}.
Returns with an array with table name, columns, and indexes.

db_list_columns

Usage $smcFunc['db_list_columns'] (table_name, detail)

with db_extend('packages');
This function returns the current columns in a table in a multi-dimensional array
If you need to specific the database prefix use {db_prefix}.
If 'detail' is specified a formated array will be returned of the column info, otherwise the plain straight column info is returned. The detailed array is 'name', 'null', 'default', 'type', 'size', 'auto'.

db_list_indexes

Usage $smcFunc['db_list_indexes'] (table_name, detail)

with db_extend('packages');
This function returns the current indexes in a table in a multi-dimensional array
If you need to specific the database prefix use {db_prefix}.
If 'detail' is specified a formated array will be returned of the index info, otherwise the plain straight index info is returned. The detailed array is 'name', 'type', 'columns'

db_remove_column

Usage $smcFunc['db_remove_column'] (table_name, column_name, parameters, error)

with db_extend('packages');
This function removes a column
Table_name can have a database prefix. If you specific a database prefix, add 'no_prefix' to the paramaters.

db_remove_index

Usage $smcFunc['db_remove_index'] (table_name, index_name, parameters, error)

with db_extend('packages');
This function removes a index
Table_name can have a database prefix. If you specific a database prefix, add 'no_prefix' to the paramaters.

Developing SMF

@@ Line 260: / Line 260: @@
 ===db_calculate_type===
 '''Usage''' $smcFunc['db_calculate_type'] (type_name, type_size, reverse)
-* with db_extend('packages');
-* This function will calculate the type and size for a column.
+This function will calculate the type and size for a column.
+'''Parameters'''
 * type_name should be the type of the column.
 * type_size contains the size of the column (can be empty
+* reverse whether or not to reverse things
+'''Returns''' ''array'' the first value is the type, and the second value is the size
 ===db_change_column===

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