Linking Existing Components to Your Company Database

This document provides detailed information on linking existing Altium Designer components to an external database using Altium Designer's database link feature.

A common requirement for many organizations is to link from the electronic CAD components to the company's central component database. Altium Designer supports this by providing the ability to link existing components to records in the company database, through the creation and use of a database link file. The database link file is added to your design project or library package, allowing you to link from components already placed on schematic sheets or, more typically, defined components in a source schematic library, respectively.

Once linked, you can transfer mapped information from the database records to design parameters in the components using the Update Parameters From Database command. This information can then be included in the final Bill of Materials (BOM), ready for component procurement.

A Word About Linking Choices...

Altium Designer provides two methods of linking from a component to a database – using either a Database Link file (*.DBLink) or Database Library file (*.DBLib) respectively. The former provides an efficient means of linking and keeping the components used in your design (or libraries) synchronized with the data entered in the database. The latter takes this proven linking efficiency and adds to it the freedom to be able to place a component directly from the database – in essence creating the component dynamically from the information stored for it in the corresponding database record.
Before launching into the greater depths of the database link feature, it is worth discussing the differences between these two methods, in regard to the way you use them.

Linking using a Database Link file (*.DBLink)

Using this method, the Database Link file defines linkage between the schematic component and a matched record in a database. The record match is established by key field linking, which can be a single key field (for example a part number), or multiple key fields (by defining a Where clause).
With this method of linking, the model and parameter information for the component must be predefined as part of the Altium Designer library component. The library component must also include the necessary key field information as part of it's definition. Once this has been defined you add a Database Link document to your Library Package or Design project, then you can synchronize the component information (parameters) with the contents of fields in the database.
Although each physical component defined by each database record does not need to map to a unique Altium Designer library component – many database components can share the same component symbol – this method of linking would typically be used in a "one database record-to-one Altium Designer component" fashion. The unique Altium Designer component can either be an instance placed on a schematic sheet, or a unique component in a component library.
With DBLink-style database linking, you include the Database Link file with the project.

Linking using a Database Library file (*.DBLib)

Using this method, the Database Library file also defines the linkage between the schematic component and a matched record in a database. Again, the record match is established by key field linking, which can be a single key field (for example a part number), or multiple key fields (by defining a Where clause).
With this method of linking the component symbol, model and parameter information for a component is stored as part of the record definition for that component in the external database. The referenced schematic component (in an underlying component library (*.SchLib)) is simply an empty shell, with a defined symbol only. There are no linked models and no defined design parameters.
When the component is placed, its parameter and model information is created on-the-fly, using the corresponding fields in the matched database record and in accordance with defined mapping. One or more of these parameters will then be used to maintain an ongoing link back to the database, as per the matching criteria defined, enabling future synchronization after placement.
This method of linking, due to its dynamic creation of components at the time of placement, lends itself very well to being used in a "many database records-to-one Altium Designer component fashion.
Unlike the DBLink-style of database linking, whereby the DBLink file must be included with the project, the DBLib file need not be added to the project. The resulting database library simply needs to be made part of the Available Libraries – accessible by the Libraries panel. Remember, the Available Libraries can consist of Project Libraries, Installed Libraries or libraries found along specified search paths.
You would typically configure DBLib files in a library-oriented fashion. For example you might have one for all the resistors detailed in your company database, another for capacitors, and so on.

Creating the Database Link File

As mentioned, the backbone of the database link feature is the Database Link file. This file is created and managed using Altium Designer's DatabaseLink Editor (Figure 1).

The DatabaseLink Editor becomes active when the active document in the main design window is a *.DBLink file. Create a new file of this type by:

• using the File » New » Database Link File command
• right-clicking on the project's entry in the Projects panel and choosing Add New to Project » Database Link File from the pop-up menu that appears.
  Database Link files, when added to a project, appear in the Projects panel under the Settings\Database Link Files sub-folder.

Connecting to an External Database

Table and mapping data will only appear in the Editor's main display window after the active Database Link file is successfully connected to the required external database. Connection is defined using the controls provided in the Source of Connection region of the window (Figure 2).

Any database which provides OLE DB support can be connected to. The options provided in this region of the window each use an OLE DB connection string to connect to the target database. Some databases may not offer OLE DB support. However, virtually all Database Management Systems in use today can be accessed through the Open Database Connectivity (ODBC) interface. The database link feature uses Microsoft's ODBC provider, which allows an ADO (ActiveX Data Object) to connect to any ODBC data source. The result is that any ODBC database can be connected to. The OLE DB provider for the ODBC database is specified as part of the connection string.

Fast Connection to Access and Excel Databases

The Select Database Type option simply offers an expedited method of creating a connection string when the target database has been created using Microsoft Access or Microsoft Excel. Using this option, simply select the database type and then browse to and select the required database file. The corresponding connection string will automatically be composed and entered into the field for the Use Connection String option.
The full path can be specified or you can opt to store the path relative to the Database Link file.

Building a Connection String

If your company database is not Access or Excel-based, and you want to build the connection string explicitly, simply enable the Use Connection String option and then click the associated Build button to the right. The Data Link Properties dialog will appear (Figure 3).

The OLE DB Provider – Microsoft Jet 4.0 – is set by default on the Provider tab of the dialog and hence the dialog opens at the Connection tab. This is the default provider setting for new Database Link files and is also used to connect to Access database files (*.mdb). Change the provider as necessary.
From the Connection tab simply enter the name (including path) of the database you wish to connect to. Alternatively, use the ... button to open a dialog from where you can browse to and open the required file.

If your database requires login permission enter this as required, along with any other advanced settings available from the Advanced tab of the dialog. The All tab provides a summary listing of link options defined, as well as extended options relating to the chosen OLE DB Provider. Options can be modified as required from this tab.
Once link options have been defined you can check for successful connection by clicking on the Test Connection button (on the Connection tab). A successful connection will yield a confirmation dialog to that effect.

Specifying a Data Link file

If the data source to which you wish to connect is described using a Microsoft Data Link file (*.udl), simply enable the third of the connection options – Use Data Link File – and click the associated Browse button to locate the required file. A Data Link File is essentially a storage vessel for a connection string.

Proceeding with Connection

After defining the connection to the external database, the text of the Connect button will become bold, signifying that you can proceed with the connection. If the connection details are correct, the table and mapping information for the target database will be loaded into the Database Link document. The text on the Connect button will change to Connected and the button will be grayed-out.

If there is a problem with the connection details, for example a connection string is built incorrectly or a path is entered erroneously, connection will fail and a message will appear alerting you to this fact (Figure 4).

Check your connection settings and click the Connect button again.

After successful initial connection, and after saving the Database Link file, the connection will be made automatically each time the file is opened, provided the target database's location and filename are not changed.

Database Table Listing

After successful connection to the external database, table and mapping data will be loaded. The left-hand side of the display window lists all tables that exist in the connected database (Figure 5).

The Enable option next to each table entry allows you to control whether or not that table is to be used when updating parameters from the database.
As you click on a table entry in the list, its icon changes from  to in order to distinguish it as being the currently active table. The table – with all its data – appears on the Table Browser tab of the display window (Figure 6). This is a non-editable copy of the table and allows you to quickly refer to its contents, without having to launch the external database itself.

Specifying Matching Criteria

In order to update part parameter information with that stored in fields of the external database, each part in the design must first be 'matched' with one row from one table in the database. The Field Settings region of the main display window (Figure 7) allows you to define the matching criteria – either a simple, single key lookup, or a more advanced match using a Where clause.
Matching criteria is specified on a per-table basis.

Single Key Lookup

If the Single key lookup option is enabled (default) the Database field and Part parameter fields become available. The former lists all of the available field names (column headers) in the active table of the database. The latter lists all of the parameters found across all parts in the design – both system and user-defined parameters. Note that the drop-down list for the Part parameter field will only become populated after compiling the parent project.
Use these fields to specify the matching between one field in the table and one parameter in a part (and typically common to all parts). Typically, the matching field in both cases is something that uniquely identifies each component in the external database, such as a Part Number. The chosen lookup field is distinguished on the Field Mappings tab of the window by the Design Parameter entry shown as grayed-out.

When using the Update Parameters From Database feature, information is read from the chosen key parameter in the placed schematic components and then searched for in the chosen (key) field of the database – across all enabled tables. When there is a match, information from other cells in that record of the parent table can then be taken back to the mapped parameters in the schematic component.

Advanced Matching – the Where Clause

While the Single key lookup option works well if there is a unique part number/id to match on, it is not so effective when matching by a parameter that is not unique, such as capacitance or resistance. In this case the more advanced Where clause should be used, enabling you to specify multiple key matching in order to link the schematic component to the required row in the relevant database table.
In its simplest form the Where clause (written using SQL syntax) reflects the chosen entries that define the single key lookup. For example if the Database field was chosen to be Part Number and the unique Part parameter (existing for all parts in the design) was chosen to be Part Number, the entry for the Where clause would be:
[Part Number] = '{Part Number}'

The square brackets around the database field (table column) are quote characters, as specified in the Advanced tab of the Database Connection dialog (Figure 9).

Access this dialog either by clicking on the Advanced button in the Source of Connection region of the window, or from the main Tools menu.
The curly brackets (braces) specify that the entry being referenced is a design parameter. The single quotes are used to specify the design parameter be treated as a string, as opposed to a number (no quotes). The type matching is very important, as SQL is type sensitive. The design parameter should be made the same type as the column in the database.
Using standard SQL syntax, the Where clause can then be extended to match using multiple Database field/Part parameter entries, for example:
[Capacitance] = '{Capacitance}' AND [Tolerance] = {Tolerance} AND [Manufacturer] = '{Manufacturer}'
In this case a single record in the relevant table of the database would be linked to using three different design parameters. Notice that the entry for the Tolerance design parameter is not quoted. This means that the column type in the associated table of the database is Number and not String.
Using standard SQL syntax you can conceivably make the Where clause as simple or as complicated as you like. An example of a more complicated clause might be:
[Tolerance] BETWEEN {Min Tolerance} AND {Max Tolerance} AND [Price] <= {Max Price} AND [Manufacturer] IN ('{Preferred Manufacturer 1}', '{Preferred Manufacturer 2}')

In this case, the table would be queried for matching parts based on three database fields – Tolerance, Price and Manufacturer. The tolerance must lie in the range defined by the Min Tolerance and Max Tolerance design parameters. The price must be less than or equal to that specified in the Max Price design parameter and the manufacturer can be any of the two candidates specified by the Preferred Manufacturer 1 and Preferred Manufacturer 2 design parameters.

Creating a Part Parameter

If no suitable parameter exists in your Altium Designer components – for use as the Part parameter for matching purposes in the DBLink file – you will need to create one. Addition of the 'base' parameter can be achieved quickly using either the Parameter Manager or the relevant Inspector panel.

Adding a Parameter using the Parameter Manager

To add a new parameter using the Parameter Manager, from a schematic document (or schematic library document) choose Tools » Parameter Manager from the main menus. The Parameter Editor Options dialog will appear. To add the new parameter to all parts, ensure that the Parts option is enabled in the Include Parameters Owned By region, and All Objects is set as the criteria (Figure 10).
 

Clicking OK will present the Parameter Table Editor dialog, showing all parameters currently 'owned' by all part objects on schematic source documents in the active project (or schematic components in the active schematic library). Simply click on the Add Column button and use the Add Parameter dialog that appears to define the name for the parameter (Figure 11). Ensure that the Add to all objects option is enabled, so that the new parameter will be added to all parts. It is best to leave the Value for the parameter unassigned – at this stage you just want to get the parameter added to each part. Bear in mind however, that to effectively link to a corresponding record in the database, the value for the parameter will need to be defined afterwards on a per-part basis.

Once the new column has been added, click the Accept Changes (Create ECO) button. Use the Engineering Change Order dialog that appears to validate and then execute the changes – adding the parameter to each of the required parts.

Adding a Parameter using the Inspector Panel

A new parameter can be added to selected parts using an Inspector-based panel. The following procedure outlines the case when you wish to add the same unique parameter to all components in the active schematic library document, using the SCHLIB Filter and SCHLIB Inspector panels.

Firstly, select all components in the library, using the SCH Filter panel and a query of IsPart. Ensure that the Whole Library option is enabled, otherwise only the active library component will be considered. In the SCHLIB Inspector panel, you can verify that all components have been selected, then add the required parameter using the Parameters region of the panel.
Simply click inside the field to the right of the Add User Parameter entry and, not entering a value, press Enter. In the dialog that appears, enter the name for the required parameter. After clicking OK, the parameter will be added to the selected components, and appear as a parameter entry in the Parameters region of the SCHLIB Inspector panel (Figure 14).

Mapping Database Fields to Design Parameters

  Design parameters for existing components – either those placed on the source schematic sheets of a design project, or those defined in a schematic component library that has been added to a library package – are updated with externally-stored information from a company database using the Update Parameters From Database command, available from the main Tools menu when the schematic document/schematic library document is active.

When a match occurs between a design component and a record in a table of the linked database, what happens next is determined by mapping and update information specified in the Database Link file. These settings are performed on the Field Mappings tab of the DatabaseLink Editor's main display window (Figure 15). Mapping and update options are specified on a per-table basis.

Parameter Mapping

The first two columns (from the left) on the Field Mappings tab allow you to control which information from the database is to be mapped to the component's parameters.

The Database Field Name column lists all field (column) names in the currently active table of the database. The Design Parameter column allows you to specify the design parameter that should be mapped to the corresponding field in the database.
  Initial mapping is performed automatically upon connection to the database, with all database fields mapped to design parameters using the same names. For example, if a field in the database is called Tolerance, a design parameter with the name Tolerance will be mapped to it. You can change the name for a design parameter simply by:

• clicking in its cell and typing the new name directly
• using the cell's associated drop-down list to choose an existing design parameter (provided the parent project has been compiled beforehand).
  You may have a large number of data fields associated with a component in the database, not all of which you will want, or even need, added as design parameters to the existing design component. Much of this information may only be required when generating a Bill of Materials. The Report Manager includes an option that allows you to add parameter information to a BOM, directly from a linked database – allowing you to reduce the amount of information that gets 'carried' with the schematic source documents. For more information, refer to the section Adding Database Information Directly to a BOM.
  For fields that you explicitly do not want mapped from the database, set the Design Parameter entry to None. Unmapped database fields are distinguished on the tab by the use of a red cross icon ( ). Mapped database fields are distinguished by a green tick icon ( ).

Parameter Update Options

The remaining columns on the Field Mappings tab (Figure 15 previously) allow you to specify the actions taken for parameters, when updating a component using the Update Parameters From Database command. In the following descriptions, the term Altium Designer component is used to represent a placed component on a schematic sheet, or a defined component in a schematic component library (which is part of a library package).
The four columns are as follows:

• Update Values – a cell in this column is used to determine the action that should be taken if the parameter exists for the Altium Designer component and in the database, but the values are currently different. Choose to update the parameter of the Altium Designer component with the value stored in the database, or not to update at all.
• Add To Design – a cell in this column is used to determine the action that should be taken if the parameter is found in the database but does not exist for the Altium Designer component. You can choose to add/not to add the parameter or add the parameter only if it has a value assigned to it in the database.
• Visible On Add – a checkbox in this column is used to determine whether a newly added parameter is made visible for the Altium Designer component (enabled) or not (disabled).
• Remove From Design – a cell in this column offers the converse of the Add To Design field, i.e. what action to take if the parameter is found to exist for the Altium Designer component, but not in the database. You can choose to not remove the parameter at all, or only remove it if it has no value assigned to it in the database.
  Initially, the Update Values, Add To Design and Remove From Design fields for each mapped database field will be set to the entry Default, and the Visible On Add option will be disabled, as illustrated in Figure 16.

Looking at Figure 16 there are three important points to make regarding update options:

• Unmapped database fields will have no associated update options.
• The key field (e.g. Part Number in Figure 16) will have no associated update options. This field is solely used for matching purposes.
• A setting of Default causes an update option to follow its corresponding default definition, as specified in the Database Link Options dialog (Tools » Options). This dialog can also be accessed by clicking the Options button in the Field Settings region of the main window.

The third point is beneficial in that it allows you to specify update options from a central location and then point to that location when defining the update options for each mapped field. That is why the Default entry is loaded automatically into the relevant update fields upon mapping a database field to a design parameter.

Should you wish to override the default setting for an update option, simply click inside the relevant update field on the Field Mappings tab and then click again to access a drop-down providing the applicable update choices. (Figure 18).

In this way, you have full control over how the parameters in the design are updated. You can set all fields to Default and make the required update decisions from the Database Link Options dialog, set each update field individually, or have a mixture of the two – the decision is entirely yours to make as you see fit. The update, when performed, is carried out through use of an Engineering Change Order dialog. If at this stage there are updates that you would prefer not to make, you can simply opt to not include those particular changes – giving you the final and ultimate say in which design parameters get updated .

Ensuring Synchronicity

After the mapping and update options have been specified in the Database Link file as required, and the file saved, you will be in a position to pass information from the database to the mapped parameters of Altium Designer components. Remember, the chosen key field parameter is used to ensure that an Altium Designer component retains its link to the corresponding record for that component in the external database. This means that at any stage in the future, changes to parameter information in the database can be easily passed back to the Altium Designer component, synchronizing the two. Updates are performed using the Update Parameters From Database command, available from the Schematic Editor's main Tools menu.

Dual Synchronization – DBLib/SVNDBLib and DBLink

You may have an existing design project where the majority of the placed parts have been linked to an external database using a DBLink file. Design changes may result in additional circuitry, the components for which might be placed using the database library feature. The associated DBLib/SVNDBLib file could, quite conceivably, point to a different external database.
When using the Update Parameters From Database command, all linked parameters for placed components will be queried – across all linked databases, irrespective of the linking method used – and detected differences for those parameters displayed in the Select Parameter Changes dialog.
If the same database field has been used for matching in both the DBLink and DBLib/SVNDBLib files, the database linked by the DBLink file will be searched first for a match, followed by the database linked to by the DBLib/SVNDBLib file. If the component is present in both databases, you could quite possibly match and update from the wrong external record.

Adding Database Information Directly to a BOM

 
Source information for a Bill of Materials (BOM) has, in the past, been taken from the parameter information of the placed components for the design. But that can lead to a lot of information attached to a schematic that is only ever used for the BOM. If your placed Altium Designer components are linked to an external database using a DBLink file, the BOM Generator is able to extract any other record information that has not been added to the components as design parameters.
When configuring the Bill of Materials report using the Report Manager, simply enable the Include Parameters from Database option. This option will only be available if one or more components in your design are linked to an external database. In the parameter listing, the icon is used to distinguish a parameter that exists for one or more placed components in a linked external database.