Microsoft Office Tutorials and References
In Depth Information
Connecting to Data
Connecting to Data
When the ECS receives a request to refresh one or more data connections (either by opening a workbook
with an implicit refresh on open, or an explicit refresh operation coming from the user), it performs the
following steps for each connection:
1.
Determine which connection to use. The ECS might use a connection file from a DCL.
2.
Determine the credentials to connect to the data (such as SSO credentials for a single sign-on).
3.
Look for a cached version of the data queries that can be used. If so, the ECS will use it and not
continue with the query.
4.
Open a connection to the data source or use an existing connection from the connection pool.
5.
Perform the query and store the results in the cache.
6.
Continue calculating the workbook and returning the results to the WFE.
This sequence is a high-level description of the flow. The rest of this chapter will detail each of these steps.
Figure 5-1 shows the components involved in external data queries.
Browser
SharePoint
Document
Library
EWA
Data
Connection
Library
ECS
Single
Sign On
Excel
Services
Microsoft Office
SharePoint Server
Database
Figure 5-1
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