The entity relationship design of MyEclipse

1. Visualizing entity relationships with ER graphs

MyEclipse Er-designer helps you visually manage relational databases, from the design lifecycle through to the implementation and maintenance of this series of processes. At the same time MyEclipse Er-designer also provides a visual model of the existing database. Because of the entity-relationship (ER) model of Er-designer's reverse engineering database, the database connector in Er-designer is used to access the database's metadata. This shows that the Er-designer rendering model uses the ER of the Information Engineering (IE) system as an Entity Relationship Diagram (ERD). At any time, Er-designer can accurately reflect the database's ERD to the current database state. The ER is designed to include a complex tabular relationship and layout engine that enables it to work out the ERD quickly.

ER diagram2. Basic description of the symbol

Er-designer support for information engineering symbols. In the process of reverse engineering, the parent-child relationship described is the only cardinality of the child entity. Describes an annotation relationship, noting the details of each table, such as the columns defined in the table, the type of column, its role, and whether it is defined as the primary or foreign key. The following describes the meanings of the icons and text styles used when defining the details in a table.

2.1 Positioning Table

In Er-designer, you can locate a table by dragging it to any new location, and any migrated operation can be undone using the Eclipse Undo command or the equivalent keyboard shortcut (for example, CTRL + Z). When a table is selected, it displays a sharp, highlighted background color. For example, the Jobs table is selected.

Example Entity relationships2.2 Relationship

A relationship is described as a tagged connection between two entities of a database table, and the label of the connection is based on the pattern: parenttable (column1, ...). ) = ChildTable (Column1, ... Mapping The direction arrow label next to the relationship label is from the parent table to the child table (-a). The name of the foreign KEY constraint is displayed when you span a connection. For example, the entity relationship image described in the above example JHIST_JOB_FK constraints, just under the bright blue text relationship. The following table describes the annotations for relationships in Er-designer.

2.3 Visualizing grids, labels, table calibrations, and sizing tables

Er-designer provides a visual grid, grid calibration, and table sizing tools to help you manually layout tables and beautify relationship routing.

Grid

To turn on/off the Visual Grid feature, select Er-designer, and select View>grid from the menu.

Toggle visual grid on/off

Grid calibration

Calibrate the grid functionality by limiting their position to fit vertically and horizontally with grid lines to facilitate manual calibration of tables and relationships. This feature is activated when the mesh does not need to be visible. To turn off/turn on the grid feature, select Er-designer, and select View>snap from the menu.

Toggle Snap To Grid switch

Relationship Label

The relationship labels between the tables are displayed by default, in order to switch labels clearly, select Er-designer, and select View>relationship Labels from the menu.

Toggle switch for Visual relationship labels

Horizontal and vertical alignment tools

The Er-designer Table Calibration tool is in the MyEclipse toolbar. Select the two or more tables you want to align, and then choose Alignment from the MyEclipse toolbar.

Table alignment on the toolbar

Adjust Table size Tool

Er-designer Adjust table size tool in MyEclipse toolbar. Select the two or more tables you want to align, and then choose Resize from the MyEclipse toolbar.

Table adjustment style on the toolbar3. Table Positioning function

Navigating large ER diagrams to find tables is undoubtedly cumbersome, and in order to simplify this process, Er-designer provides two table positioning capabilities. The first is a schematic diagram of the table that depicts the database in the tree list, followed by a table locator, which provides a quick table name search and location.

Displays the Job_history table that is selected in outline view and the corresponding highlighted ER chart symbol.

Find a table using outline view

In addition to using outline view to find a table, Er-designer also provides a table locator, which is a pop-up window with fast text search functionality. You can start the table locator either from the Er-designer right-click shortcut menu or from the navigation menu bar, the Outline view toolbar, or by pressing ALT + F3.

Table Locator Window4. Er-designer Preferences

You can customize the Er-designer preferences page. To access the Er-designer preferences page, select Window>preferences, expand Myeclipse>database Explorer, and select Er-designer.

Er-designer's Preferences page5. Resources

• Introduction to Data modeling

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The entity relationship design of MyEclipse