View source for Kexi/Migration/CSV/Add support for appending CSV data to an existing table

*Status: DONE
*{{wish|305505}}

==Rationale==
Appending CSV data to an existing table gives a simple means for merging CSV data chunks in one step.

==Assumptions & Requirements==
*The data should be appended to the existing table, without changes made to the 
*Data is in largely the same format (regarding column or data types) as the data used to create the original table, to achieve this:
**Data types for columns should be taken from the schema of the destination table
**Column names stay untouched in the destination table, however autodetection should be still used to figure out value of the "First row contains column names" option; the option can be changed in the

*Conflicts resolutions:
**Data type violations (for example when importing string when numeric value is expected): TODO - for 2.6 we need to have friendly error message at least
***Future: propose skipping conflicting values
**Primary key violations: TODO - for 2.6 we need to have friendly error message at least
***Future: propose skipping records with conflicting values or replacing the old records with new ones
**Future: unique key violations: TODO

==GUI Design==
Existing GUI is based on single dialog as follows:<br/>
[[Image:Kexi CSV Import Dialog.png|500px]]

Switching to KAssistantDialog is needed.
Proposed pages:
1. File selection (implementation already exists but uses separate modal dialog)

2. Data preview and options (implementation already exists but uses separate modal dialog)

3. Destination Selection page:
*[KexiCommandLinkButton 3.1]: Import data into a new table
*[KexiCommandLinkButton 3.2]: Append data to existing table

4.1. (when 3.1 clicked) Save Object As (implementation already exists but uses separate modal dialog)

4.2. (when 3.2 clicked) Select destination table
*use KexiFieldListView for the list of tables
*double click on name should do the same as clicking Next button

5. Importing
*display progress bar
*while importing disable all buttons but cancel
*hide the progress when done with importing and display "Data has been successfully imported to table "%1" (implementation already exists but uses separate modal dialog)
*available buttons should be: "Open..." and "Close"; "Cancel" should not be displayed after importing (implementation already exists but uses separate modal dialog)