.. _erd_tool: ***************** `ERD Tool`:index: ***************** The Entity-Relationship Diagram (ERD) tool is a database design tool that provides a graphical representation of database tables, columns, and inter-relationships. ERD can give sufficient information for the database administrator to follow when developing and maintaining the database. The ERD Tool allows you to: * Design and visualize the database tables and their relationships. * Add notes to the diagram. * Auto-align the tables and links for cleaner visualization. * Save the diagram and open it later to continue working on it. * Generate ready to run SQL from the database design. * Generate the database diagram for an existing database. * Drag and drop tables from object explorer to the diagram. .. image:: images/erd_tool.png :alt: ERD tool window :align: center You can open multiple copies of the ERD tool in individual tabs simultaneously. You can also generate an ERD from a database, schema or a table. * The ERD for database will fetch all the tables from all the schemas of the database and plot them with foreign key links. * The ERD for schema will fetch all the tables from a schema and plot them with foreign key links. If any table refers to a table in another schema, then that link/foreign key will be removed. * The ERD for table will fetch all the tables linked directly or indirectly to mentioned table. You can change the depth of traversal from :ref:`Preferences `. Toolbar ******* The *ERD Tool* toolbar uses context-sensitive icons that provide shortcuts to frequently performed tasks. The option is enabled for the highlighted icon and is disabled for the grayed-out icon. .. image:: images/erd_tool_toolbar.png :alt: ERD tool toolbar :align: center Hover over an icon on Toolbar to display a tooltip that describes the icon's functionality. File Options ************ .. table:: :class: longtable :widths: 1 4 1 +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | Icon | Behavior | Shortcut | +======================+===================================================================================================+================+ | *Open File* | Click the *Open File* icon to load a previously saved diagram. | Cmd/Ctrl + O | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Save* | Click the *Save* icon to perform a quick-save of a previously saved diagram, or to save the | Cmd/Ctrl + S | | | diagram to a file. | | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Save as* | Click the *Save As* to open a new browser dialog and specify a new location to save the diagram. | Ctrl + Shift + | | | You need to click the down arrow beside the save button to see *Save As*. | S | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ Export Options ************** .. table:: :class: longtable :widths: 1 4 1 +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | Icon | Behavior | Shortcut | +======================+===================================================================================================+================+ | *Generate SQL* | Click the *Generate SQL* icon to generate the DDL SQL for the diagram and open a query tool | Option/Alt + | | | with the generated SQL ready for execution. | Ctrl + S | | | You can select the option *With DROP Table* if you wish to have DROP Table DDL statements before | | | | each CREATE Table DDL. You can see the option by clicking the down arrow beside the SQL button. | | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Download image* | Click the *Download image* icon to save the ERD diagram in a image formate | Option/Alt + | | | | Ctrl + I | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ Editing Options *************** .. table:: :class: longtable :widths: 1 4 1 +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | Icon | Behavior | Shortcut | +======================+===================================================================================================+================+ | *Add table* | Click this button to add a new table to the diagram. On clicking, this will open a table dialog | Option/Alt + | | | where you can put the table details. | Ctrl + A | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Edit table* | Click this button to edit a table on the diagram. On clicking, this will open a table dialog | Option/Alt + | | | where you can change table details. This will enable when a table is selected. | Ctrl + E | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Clone table* | Click this button to clone the complete table structure, name it with a auto generated name and | Option/Alt + | | | put it in the diagram. | Ctrl + C | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Drop table/link* | You can drop a table or link using this button. You need to select a table or link and click on | Option/Alt + | | | this button to drop it. | Ctrl + D | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ Table Relationship Options ************************** .. table:: :class: longtable :widths: 1 4 1 +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | Icon | Behavior | Shortcut | +======================+===================================================================================================+================+ | *1M* | Click this button to open a one-to-many relationship dialog to add a relationship between the | Option/Alt + | | | two tables. The selected table becomes the referencing table and will have the *many* endpoint of | Ctrl + O | | | the link. | | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *MM* | Click this button to open a many-to-many relationship dialog to add a relationship between the | Option/Alt + | | | two tables. This option will create a new table based on the selected columns for the two relating| Ctrl + M | | | tables and link them. | | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ Node Color Options ************************** .. table:: :class: longtable :widths: 1 5 +----------------------+----------------------------------------------------------------------------------------------------------+ | Icon | Behavior | +======================+==========================================================================================================+ | *Fill Color* | Use Fill Color to change the background color of a table node. This is helpful if you want to | | | identify a of group tables. Once set, all the newly added tables will take the same color. | +----------------------+----------------------------------------------------------------------------------------------------------+ | *Text Color* | Use Text Color to change the text color of a table node based on the fill color to make text | | | easily readable. | +----------------------+----------------------------------------------------------------------------------------------------------+ Utility Options *************** .. table:: :class: longtable :widths: 1 4 1 +-------------------------+------------------------------------------------------------------------------------------------+----------------+ | Icon | Behavior | Shortcut | +=========================+================================================================================================+================+ | *Add/Edit note* | Click this button to make notes on tables nodes while designing the database. | Option/Alt + | | | | Ctrl + N | +-------------------------+------------------------------------------------------------------------------------------------+----------------+ | *Auto align* | Click this button to auto align all tables and links to make it look more cleaner. | Option/Alt + | | | | Ctrl + L | +-------------------------+------------------------------------------------------------------------------------------------+----------------+ | *Show details* | Click this button to toggle the column details visibility. It allows you to show few or more | Option/Alt + | | | column details. | Shift + D | +-------------------------+------------------------------------------------------------------------------------------------+----------------+ | *Cardinality Notation* | Change the cardinality notation format used to present relationship links. Options available | | | | are - Crow's Foot Notation and Chen Notation. | | +-------------------------+------------------------------------------------------------------------------------------------+----------------+ Zoom Options ************ .. table:: :class: longtable :widths: 1 4 1 +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | Icon | Behavior | Shortcut | +======================+===================================================================================================+================+ | *Zoom to fit* | Click this button to zoom in/out automatically and fit all the tables to the view. | Option/Alt + | | | | Shift + F | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Zoom in* | Click this button to zoom in the diagram. | Option/Alt + | | | | Shift + "+" | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ | *Zoom out* | Click this button to zoom out the diagram. | Option/Alt + | | | | Shift + "-" | +----------------------+---------------------------------------------------------------------------------------------------+----------------+ Table Dialog ************ .. image:: images/erd_table_dialog.png :alt: ERD tool table dialog :align: center The table dialog allows you to: * Change the table structure details. * It can be used edit an existing table or add a new one. * Refer :ref:`table dialog ` for information on different fields. Table Node ********** .. image:: images/erd_table_node.png :alt: ERD tool table node :align: center The table node shows table details in a graphical representation: * The top bar has a *details toggle button* that is used to toggle column details visibility. There is also a *note button* that is visible only if there is some note added. you can click on this button to quickly change the note. * The first row shows the schema name of the table. Eg. *public* in above image. * The second row shows the table name. Eg. *users* in above image. * All other rows below the table name are the columns of the table along with data type. If the column is a primary key then it will have lock key icon eg. id is the primary key in above image. Otherwise, it will have column icon. * you can click on the node and drag to move on the canvas. * Upon double click on the table node or by clicking the edit button from the toolbar, the table dialog opens where you can change the table details. Refer :ref:`table dialog ` for information on different fields. The One to Many Link Dialog *************************** .. image:: images/erd_1m_dialog.png :alt: ERD tool 1M dialog :align: center The one to many link dialog allows you to: * Add a foreign key relationship between two tables. * *Local Table* is the table that references a table and has the *many* end point. * *Local Column* the column that references. * *Referenced Table* is the table that is being referred and has the *one* end point. * *Referenced Column* the column that is being referred. The Many to Many Link Dialog **************************** .. image:: images/erd_mm_dialog.png :alt: ERD tool MM dialog :align: center The many to many link dialog allows you to: * Add a many to many relationship between two tables. * It creates a relationship tables having columns derived from the two tables and link them to the tables. * *Left Table* is the first table that is to be linked. It will receive the *one* endpoint of the link with the new relation table. * *Left Column* the column of the first table, that will always be a primary key. * *Right Table* is the second table that is to be linked. It will receive the *one* endpoint of the link with the new relation table. * *Right Column* the column of the second table, that will always be a primary key. The Table Link ************** .. image:: images/erd_table_link.png :alt: ERD tool table link :align: center The table link shows relationship between tables: * The single line endpoint of the link shows the column that is being referred. * The three line endpoint of the link shows the column that refers. * If one of the columns that is being referred or that refers is removed from the table then the link will get dropped. * you can click on the link and drag to move on the canvas. The Table Notes *************** .. image:: images/erd_table_note.png :alt: ERD tool table note :align: center * You can use the notes popup to mark some notes while designing the database. * You open the pop-up using the toolbar note button. * If some note is added to a table then it will have notes button on the table node. You can click on the button to check/update notes.