what is the difference between control flow and data flow in ssis? thanks siddharth

There is good documentation on SSIS package elements in the Books Online (http://msdn.microsoft.com/en-us/library/ms139914.aspx). At a high level, the control flow specifies the ordering and precedence of tasks within a package while data flow tasks specifies how data moves between sources and destinations along with the associated transformations. Dan Guzman, SQL Server MVP, http://weblogs.sqlteam.com/dang/

thanks..so how do i meege the two .for example... i have a data flow like this....sql sorce connection --> data conversion --> detination db. but i also want to, lets say a alter table before (or after the data conversion)...so to do alter table, i have to use a sql task which u only see in tool bar when you switch to control flow tab ....so how do these two views/tabs merge/work together? in the end i want package to look like this.. sql sorce connection --> ---->data conversion----> sql task to alter table --> detination db thanks siddharth

sql sorce connection --> ---->data conversion----> sql task to alter table --> detination db This construct would alter the table for each row returned by the source. Do you want to alter the table multiple times? Is there some result the the conversion that affects the alter table? Dan Guzman, SQL Server MVP, http://weblogs.sqlteam.com/dang/

thanks Dan for the reply... I am just trying to understand the two tabs that see in designer, how control flow and data flow work together at conceptual level.....because there are task that only show up when you switch to control flow.....but i am assuming when you excute the package it merges whatever you put in control flow and data flow into one sequnece of excution (program start and end)....so i am unclear how these two work together. lets take the same exaple that i asked... senario one : lets say I want to exceute alter table statment for each row (which does not make lot of sense..but just for understanding the two tabs) ..how will my data flow and control flow look like in this case? senario two : I do not want to exceute alter table statment for each row ..how will my data flow and control flow look like in this case ? thanks Siddharth

senario one : lets say I want to exceute alter table statment for each row (which does not make lot of sense..but just for understanding the two tabs) ..how will my data flow and control flow look like in this case? The data flow component will be the only component under the data flow tab. When you edit the data flow component, the data flow tab will show an OLE DB Source connected to a OLE DB Command. The command (ALTER TABLE in this example) will be executed once for each row returned by the source command. Note that the contents of the data flow tab will vary depending on the selected data flow task; you can have many data flow tasks in a single package but a package has only one control flow. senario two : I do not want to exceute alter table statment for each row ..how will my data flow and control flow look like in this case ? Let's say you want to execute an alter table followed by a copy of data from one table to another with no transformations. In this case, the control flow will contain an Execute SQL Task (with the ALTER TABLE) connected to a data flow task with an on success constraint. The data flow tab will show an OLE DB Source connected directly to an OLE DB Destination. Dan Guzman, SQL Server MVP, http://weblogs.sqlteam.com/dang/