How to create a relationship diagram by using Visio - Microsoft Community
Microsoft Visio is a flexible software tool that allows users to create some As we can see in Figure 4, we have Entity Relationship (US Units) under. How to create a Chen ER Diagram Open Microsoft Visio; Click the File menu, select New, then Database, and then Database Model Diagram; On the menu. Visio Visio Visio Online Plan 2 Visio Premium Visio Standard More Less Create a relationship in a database model diagram. Remove .
Type the path and file name for the model that you want to import, or click the Browse button to locate the model file, and then click Open. In the Import dialog box, click OK. Visio imports the file and displays its progress in the Output window.
The imported tables are displayed in the Tables and Views window. In the Tables and Views window, select the tables that you want to model, and then drag them onto the drawing page.
After you create a database model diagram, the work of refining the diagram begins. You can add and customize tables and views, create relationships, and customize columns and data types.
Tables Use the Entity shape to create a table in your diagram. From either the Entity Relationship or Object Relational stencil, drag an Entity shape onto the drawing. Double-click the shape to open the Database Properties window.
Under Categories, click Definition and type a name for the table. Under Categories, click Columns, type a name, and choose a data type. Select the Req'd check box for columns that can't have null values. Select the PK primary key check box for columns that uniquely identify each row in the database table. Columns Use the Database Properties window to add or change properties for columns, including data types and primary keys.
Double-click the table in your diagram. In the Database Properties window, under Categories, click Columns. Click in the first empty Physical Name cell, and type a name. To change the data type for a column, click the column's Data Type field, and then select a data type from the list or type it into the list. For example, you can type decimal 8,2 or char To prevent null values, select the Req'd check box.
Visio database diagrams, associating columns - Stack Overflow
To specify that the column is a primary key, select the PK check box. To see more column properties in addition to those that appear when you click the Columns category, select the column and then click Edit. Relationships Relationships use primary and foreign keys to allow databases to match a row in one table with a row in a related table. You can show those relationships in your diagram. In addition, you can set their cardinality for example, one-to-many and use either Crow's feet, Relational, or IDEF1X notation to show the cardinality.
You can't show many-to-many relationships with any of these notations in the Database Model Diagram template. Create a relationship between tables: Make sure that both tables are visible in the diagram.
If you reverse engineered the model from an existing database, you may need to drag one or both from the Tables and Views window onto the drawing page. Double-click the table that you want for the primary key side of the relationship. In the grid, click the column that you want to use to uniquely identify each row in the table, and select the PK check box to set it as the primary key.
From the Object Relational or Entity Relationship stencil, drag a Relationship shape and drop it onto a blank space on the page.
Create a Database Model (also known as Entity Relationship diagram)
Connect the higher end to the table with the parent table. Connect the other end to the child table. If the second table doesn't already contain a column with the same name as the primary key, the modeler adds it to the second table as a foreign key.
If relationship lines disappear, on the Database tab, in the Manage group, click Display Options. On the Relationships tab, under Show, select the Relationships check box. Set the relationship's cardinality: In the Database Properties window, under Categories, click Miscellaneous. Under Cardinality, choose the cardinality that best fits the relationship. For one-to-many relationships, the best choice is either Zero or more or One or more.
For one-to-one relationships, the best choice is either Zero or one or Exactly one. To make other refinements to your diagram such as creating indexes, check clauses, and triggers you can do the following: Create indexes Indexes improve the performance, or speed, of your database when you run a query.
Open the database model diagram. Double-click the table to which you want to add an index, and in the Database Properties window, in the Categories list, click Indexes. In the Create Index dialog box, type a name for the index, and then click OK. In the Index Type list, select an option to create a unique or non-unique index. In the Indexed Columns list, select the Asc check box to create an index that has an ascending sort order, or clear the check box to create an index that has a descending sort order.
The database model diagram is updated.
Define a relationship in a Database Model diagram
Create views You can think of a view as a saved query. Views are particularly handy if you need to repeatedly access the same information from multiple tables, or if you want to expose the data to users without letting them change the actual tables.
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Set extended properties for tables and views Depending on your database management system DBMSyou may be able to set extended properties for tables or views to determine where they are stored.
Double-click the table or view whose extended properties you want to set, and in the Database Properties window, in the Categories list, click Extended. Create check clauses Use check clauses to ensure that the data that is entered into a column is within a particular range of values. For example, you can create a check clause that requires the data in a column called "Age" to be over Double-click the table to open the Database Properties window.
Under Categories, click Columns and then click the column that you want to add a check clause to. On the Check tab of the Column Properties dialog box, enter the constraints that you want.
The check clause is added to the Code window under Local code. Create stored procedures and user-defined functions Use stored procedures and user-defined functions to create packets of code that you can reuse to perform the same actions repeatedly.
The major difference between the two is that a user-defined function returns a value, whereas the stored procedure executes code without returning a value. Remove a relationship from a database model Click the relationship in your model and press delete. In the Delete Object dialog box do one of the following: Click Yes to remove the relationship from both the drawing and the underlying model.
Click No to remove only the line on the drawing. If you click No and later decide to add the line back into the drawing, select one of the tables in the relationship and, on the Database menu, click Show Related Tables. You can choose to always or never drop deleted relationships from the underlying model. On the Database menu, point to Options, click Modeling, and go to the Logical diagram tab.
Top of Page Define a relationship as one-to-one or as one-to-many The cardinality of a relationship describes how many rows in one table can relate to how many rows in another table. For example, one department can have many employees, but an employee can belong to only one department.
Cardinality is usually expressed as one-to-one, one-to-many, and many-to-many. In the Database Properties window, under Categories, click Miscellaneous. Under Cardinality choose the cardinality that fits the relationship best. For one-to-many relationships that would be either Zero or more or One or more. For one-to-one relationships that would be either Zero or one or Exactly one. Show relationships and their properties in a diagram You can choose to show or hide information about relationships in your diagram.
On the Database menu, point to Options, and then click Document. On the Relationships tab, check information you want to show on the diagram.