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212 lines
8.5 KiB
212 lines
8.5 KiB
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KexiDB module IDEAS, ISSUES, PROPOSALS
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Copyright (C) 2003 Jaroslaw Staniek js at iidea dot pl
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Started: 2003-08-01
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Kexi home page: Users: http://www.koffice.org/kexi/ Developers: http://kexi-project.org
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Changes:
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2005-09-16 Global BLOBs Storage
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| This document is expected to be independent of given KexiDB dirver implementation,
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| but proposals are described here are after certain decisions has been made:
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| -drivers are (by current importance): SQLite (embedded),
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| ODBC (universality reasons ), Mysql (historical reasons), PostgreSQL
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-----------------------------------------------------------------
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1. EXTENSION: Option for setting user-defined error messages on selected error types.
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Since new KexiDB has fully i18n'd user-visible messages, it outperforms other products as MSA
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(that often shows confusing message coming directly from the engine). There is possibility
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to provide users with table of error messages that they can personalize. These settings can
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be properties of table (query, form, etc.) and thus can be inherited (eg. by form from a table).
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By default, i18n'd messages from KexiDB can be presented.
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<EXAMPLE>
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Before we set our message for UNIQUE KEY conflict for table Cars (name varchar UNIQUE, price integer),
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we have got this message when try to violate 'unique' restionction:
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"There is already added one record with field 'name' set to 'Dodge' in table 'Cars'.
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This field must be unique."
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Now, we want more descriptive message: "There should be only one car named 'Dodge'!".
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We write this not as above, but rather: "There should be only one car named %field%!",
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since %field% is automatically substituted by given field value. After this we get message
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that is easier to understand for everyday user. Of course Kexi (and competitors too) never will
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be so clever as a human in building such messages automatically.
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</EXAMPLE>
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<NOTE>Inheriting messages: it will be more conventient to set up custom messages (if required)
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for table definition rather than just in form. If we set up given message in for a table, every
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form that uses this table as data source (end every query that do so) can use this message when needed.
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This note is also useful for other types of properties that can be inherited by extended objects from.
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</NOTE>
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-----------------------------------------------------------------
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2. KexiDB classes inheritance diagram
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TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO
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Object
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DriverManager
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Driver
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[DRIVER]Driver
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Connection
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[DRIVER]Connection
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[DRIVER] should be substituted by SQLite, MySQL, etc.
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These are classess to reimplement in the drivers.
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ConnectionData
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Field
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Cursor
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[DRIVER]Cursor
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FieldList
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TableSchema
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QuerySchema
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IndexSchema
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Transaction
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TransactionGuard
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BaseExpr
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NArgExpr
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UnaryExpr
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BinaryExpr
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ConstExpr
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VariableExpr
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-----------------------------------------------------------------
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3. Table schema, query schema, etc. storage
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Table or query schemas are extended with additional properties,
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usually not available from most db engines or even related to gui.
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//This table contains list of kexi object stored within project (tables, queries, etc.)
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kexi__objects
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o_id integer unsigned primary key auto_increment,
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o_type byte, //type id taken from KexiDB::ObjectTypes
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o_name varchar(200),
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o_caption varchar(200), //optional, enriched name, can contain non-latin1 characters
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o_help varchar
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//This table contains object's data, such as form's xml def.
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kexi__objectdata
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o_id integer REFERENCES kexi__objects(o_id),
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o_data varchar,
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o_sub_id varchar(200) //sometimes single object can have more than one data
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//-these can be identified by o_sub_id
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//if not needed, leave it as NULL
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//This table contains fields that are members of given kexi object.
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//Not all object types should be allowed, now allowed are tables and queries
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kexi__fields
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t_id integer REFERENCES kexi__objects(o_id),
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f_type byte,
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f_name varchar(200),
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f_length integer,
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f_precision integer,
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f_constraints integer,
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f_options integer,
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f_default varchar,
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//these are additional properties:
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f_order integer,
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f_caption varchar(200),
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f_help varchar
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//This table contains a list of parts defined for this database
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kexi__parts
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p_id integer unsigned primary key auto_increment,
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p_name varchar(200),
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p_mime varchar(200),
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p_url varchar
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TODO: add version?
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//This table contains global (predefined or not) properties for this database
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kexi__db
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db_property varchar(32),
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db_value varchar
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//Predefined properties stored in kexi__db:
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property="kexidb_major_ver", value=<major_version>
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Where: <version> is a string containing integer in textual form that denotes
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KexiDB implementation major version used to create or update this database.
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This property is useful for KexiDB library and applications to denote
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what KexiDB features could be available. This ensures backward compatibility
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and (at least in some cases) -- forward compatibility.
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property="kexidb_minor_ver", value=<minor_version>
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like above -- minor KexiDB version
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property="project_caption", value=<string>
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property="project_desc", value=<string>
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TODO: put more props. todo - creator, created date, etc. (also to KexiProjectData)
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// Global BLOBs Storage (BLOB == BINARY LARGE OBJECT)
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// Designed to store any kind of static images, sound and other binary data
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//Table:
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kexi__blobs
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o_id integer unsigned primary key auto_increment, //unique project-wide identifier of a BLOB
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o_data BLOB,
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o_name varchar(200), //optional, name of the blob,
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//can be e.g. a name of original file the data comes from,
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//can contain non-latin1 characters
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o_caption varchar(200), //optional, enriched name, can contain non-latin1 characters
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o_mime varchar(200) NOT NULL, //MIME type of a BLOB, e.g. image/jpg
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o_folder_id integer unsigned //references kexi__gallery_folders.f_id
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//If null, the BLOB only points to virtual "All" folder
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//WILL BE USED in Kexi >=1.1
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//(not yet implemented, planned for 1.1)
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//User-defined folders for better BLOBs categorizing.
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//For simplification, folders have no lowlevel name but only caption.
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//By default there are no physical folders, but only following virtual:
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//-"All" folder
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//-"Used" folder (computation of this takes some time because design of forms
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// and reports needs to be parsed)
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//-"Unused" folder (the same note as for "Used)
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//-"By type" folder with "jpeg", "png" subfolders, etc. - available by grepping using BLOB's o_mime
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kexi__gallery_folders
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f_id integer unsigned primary key auto_increment, //unique id of a folder
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f_parent_id integer unsigned //references f_id, can be null for top level folders
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f_caption varchar(200), //optional, enriched name, can contain non-latin1 characters
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f_notes varchar, //optional notes
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-----------------------------------------------------------------
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4. Extended table schema information:
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Docs available online:
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- http://kexi-project.org/wiki/wikiview/index.php?ExtendedTableSchemaInformation
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- Table Column Lookup: http://kexi-project.org/wiki/wikiview/index.php?KexiDBLookupColumns
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-----------------------------------------------------------------
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5. DEPRECATED TABLES
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//This table contains additional information for query schemas
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kexi__querydata
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q_id integer REFERENCES kexi__objects(o_id),
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q_sql varchar, //raw sql text - stored in the unchanged form entered by a user (or generated)
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q_valid boolean, //query schema may be invalid (syntactically or logically,
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//but still can be stored)
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q_parent_tab integer REFERENCES kexi__objects(o_id) //parent table of this query
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//This table contains information about fields defined in select queries
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kexi__queryfields
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q_id integer REFERENCES kexi__objects(o_id),
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f_order integer, //order of this field in query schema
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f_id integer REFERENCES kexi__objects(f_order), //may be NULL if a field is asterisk
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f_tab_asterisk integer REFERENCES kexi__objects(o_id), //if this is "single-table" asterisk
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//this member references to valid tables id, otherwise is NULL
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f_alltab_asterisk boolean //true if this is "all-tables" asterisk, otherwise false
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//This table contains information about tables used by select queries
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kexi__querytables
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q_id integer REFERENCES kexi__objects(o_id),
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t_id integer REFERENCES kexi__objects(o_id), //references to table used by given q_id
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t_order integer //order of t_id table in query schema's tables list
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