In comparison to ADO. Manifold supports ADO. In the Files of type box choose the access method desired, either choosing a common file type such as. When using a common file type, browse over to the database file and open it. When using the Data Source dialog, double-click on the data source to open it if it has already been added to the list in the Data Source dialog.
Create the data source if it has not yet been added, as is shown in the Data Source dialog topic. Choose the table to be imported or linked. When linking tables, check Read Only if you wish a read-only link. Press OK. After the initial choice of File - Import or File - Link , all dialogs are the same. The only difference is whether the data in the table is copied into the project or if it is left outside in an external file or data source.
Open the Tools - Database Console dialog. In the Data source box, specify a data source by pressing the [ In Database Console, press the Refresh button to display the contents of the data source. The upper pane will show the contents of that data source, including any tables and the fields they contain. Click on a table to highlight it.
Click on the Import button in the dialog's toolbar to import the highlighted table. Click on the Link button to link the table. Press Close. In all cases, tables that are imported or linked will appear to be part of the project like any other table. Manifold can import data from or link to a very wide range of database files and database providers.
Manifold supports use of schemas when importing or linking data from SQL Server, Oracle or similar data sources. There is no need to worry about tables that may be resident in other files or maintaining links to database systems that may be inaccessible from different systems. If other programs could alter the table if it were linked and not imported they might alter it in a way that is incompatible with the Manifold project, for example by removing a field that is used elsewhere within the project.
This limitation does not apply to external, linked tables. However, if that's what we have in mind it is usually more conceptually easier to remember what is going on by simply storing shared data in an external database, such as SQL Server Express or Oracle Express.
Of course, if we don't want to risk uncontrolled modifications this is a disadvantage. When a database is a standard archival source, always linking to it instead of copying it assures that the version in use in the project is the currently archived version. The disadvantage, of course, is that one must remember to make copies of linked tables when interchanging projects. Also, changes made in Manifold operations can result in unwanted alteration of the archival original. If we are looking at an external table in which data is unexpectedly changing, we must keep in mind the possibility that users on other machines are also working on that same table at the same time and are making changes to the data it contains.
Such columns are said to be NULL-able. Important Note when using bit Manifold Editions. The workaround for importing or exporting such files is to launch Manifold in bit mode by using the Manifold System bit shortcut, perform the export from or import into a. Linking is more complex: the data must be in some format usable in bit mode within bit Windows systems, such as a SQL Server database.
Alternatively, the data can be kept within a Manifold. A very useful aspect of linked tables in Manifold is that they are a "live" connection to the data source from which they are linked. We can make changes in the linked table and those changes will be implemented back to the data source from which the table is linked.
In particular:. All of the above capabilities apply to both standalone linked tables and tables bound to linked drawings. Scans are often so quick we might never notice the scanning sub-icon. A yellow cylinder icon in the project pane for the new data source indicates the data from that source is stored outside the project within the data source.
If we create a data source that is read-only the icon will include a small black lock to indicate we cannot change data within that data source. However, those tables do not actually exist within the non-Radian link or data source. In the case of such linked sources they are synthesized as virtual tables by Radian for Radian's use in operating that link or data source.
They are visible only to Radian and can be used only within Radian. They do not actually exist in the data source and the data source's native query engine, if one exists, will not be able to see them. Radian will use the System Data folder for a linked data source to save other housekeeping infrastructure. As convenient as it is working with data "in place" in whatever format or source it was originally, formats and sources vary widely in their technical characteristics such as speed, data capacity, robustness in the face of network or Windows glitches or ability to handle parallel processing that lets you use the full power of your computer.
Importing data into Manifold avoids such problems, but it comes with some advantages and disadvantages. Slower imports - Imports can be really slow, taking tens of seconds or even minutes for larger files. That is a one-time process. You never have to import data again once it is in Manifold. When data has been imported into Manifold it is very fast, but that one-time, initial import will be annoyingly slow for larger data. After experiencing the benefits of importing data the one-time annoyance will be forgotten.
Larger files - Manifold. In exchange for the above two disadvantages, importing data into Manifold has many advantages:. Instant open of project files - Double-click on a Manifold. Instant saves of changes - Whatever the size of the project and however many changes you make, you can save the project instantly.
That encourages frequent saves. Fast, fast, fast performance - Manifold. Part of that magic is the ability for the system to reach into the format with high efficiency in any location. Parallel processing - Manifold format automatically supports parallel processing so you can use all of cores in your computer, automatically, and not just one-eighth the power of your computer.
That is important not just for large computations but also for routine user interface work like re-projection on the fly of layers in maps so that layers in different projections can be displayed together. Larger capacity - Manifold format supports very large projects even on ordinary desktop machines, without limits that apply to older formats such as shapefiles.
Instant display of images and drawings - Enormously large images open instantly and drawings and maps nearly instantly. Panning and zooming within images and drawings is even faster. Fault tolerant - Manifold format is robust storage with numerous technical features providing increased fault tolerance against fails in hardware, Windows or network connections.
No storage can be perfect but Manifold. Perfect Projections - Manifold format automatically maintains projection information, unlike formats that depend upon accessory files such as shapefiles with. Exact data types - Precise and accurate management of data requires precision in data types.
Formats such as shapefiles which have few data types no numeric types, for example do not provide the precision and control required for modern DBMS work. Whether it is precise specification of the numeric composition of channels and data within those channels for raster data, or the precise specification of object types in vector geometry, or the precise specification of data types in tables, using Manifold format provides precision, accuracy and richness required for a central format that will be the interchange point between many different other formats, DBMS servers and other data sources.
Petabyte nested storage - Manifold format allows nesting. All the data in all those nested. That allows us to include petabytes of data within a project by nesting other projects, and to keep that vast amount of data. In an era when disk space is basically free but our time is more valuable than ever, it makes sense to trade off slightly larger files to get the above benefits.
It also make sense to tolerate slow imports of very large files on a one-time basis. Most files import quickly enough. Experienced Manifold users tend to move as much of their data as possible into Manifold project files, using.
Tech Tip: When you first install Manifold System, begin a systematic plan of converting your larger files into Manifold format during off hours. Set a reminder on your computer to import a file just before lunch hour and just before your work day ends. When you return, save the project in Manifold.
Do that on a regular basis and before you know it, all of your big files will have been imported into native Manifold storage, ready to open instantly. Apply the same plan to link into a Manifold project any files like ESRI shapefiles or MapInfo files you may some day want to edit "in place. That will build a. If in advance you systematically import or link big files and then save the results as Manifold.
Enjoy life more. Do your imports in advance. The terms projection and coordinate system are used as synonyms by Manifold. Getting it right on import: When importing data, Manifold will use whatever coordinate system the source says should be used for that data. Most modern formats used in GIS will automatically specify the coordinate system to be used. But older formats won't do that, so we have to assign the coordinate system when we import from those formats. The Info pane tells us at a glance if a coordinate system has been assigned OK.
When a data source specifies the coordinate system to use, Manifold displays the coordinate system in black color. If the coordinate system is shown in red color, we must click the coordinate system picker button and choose Assign Initial Coordinate System. When a component has been created without specifying the coordinate system or it has been imported from a format that does not specify projection information, Manifold will show the default Pseudo Mercator coordinate system as a placeholder in red color.
Red color in a coordinate system name warns us that we must assign an initial coordinate system: Click the coordinate system picker icon and use the Assign Initial Coordinate System dialog to specify what projection should be used. Do that immediately after import whenever a coordinate system appears in red text. Tech tip: What projection is used by data can be difficult to determine sometimes.
When downloading data from the web or other sources, always look for any accompanying notes or metadata information that says what projection is used for the data. For example, shapefiles that do not have a. Must be able to open the file - When importing or linking a file our Manifold session must, of course, be able to open that file.
If something about Windows permissions or policies does not allow our login or the applications we run to access a file, then, of course, we will not be able to either import the file or to link to it.
Likewise, if some other process has locked out access to the file we will not be able to import it or link to it. If some other process has opened a file read-only , then usually we will be able to import from it or link to it, so long as we link to it read-only as well. Large Imports take time - Importing data from big files can be slow while the data is converted into the special form Manifold uses internally to support fast performance.
We can add a new form or report and send the user an update without having to disturb all the data they've already entered. If you look closely at the tables in the Conrad Systems Contacts sample database Contacts.
This indicates that these tables are linked from another data source. Linking Database Files You have the choice of importing or linking data from other databases, but how do you decide which type of access is best? You should consider importing another database file when any of the following is true: The file you need is relatively small and is not changed frequently by users of the other database application.
You don't need to share the data you create with users of the other database application.
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