Ssis-661 Direct

If you must stay with a non‑Unicode destination, the following C# snippet inside a Script Component (Transformation) safely converts while logging dropped characters:

public override void Input0_ProcessInputRow(Input0Buffer Row)
if (!Row.UnicodeCol_IsNull)
// Source Unicode string
        string src = Row.UnicodeCol;
// Target encoding (1252 = Latin-1)
        Encoding targetEnc = Encoding.GetEncoding(1252, EncoderFallback.ReplacementFallback,
                                                       DecoderFallback.ExceptionFallback);
try
// Convert, replacing unrepresentable chars with '?'
            byte[] bytes = Encoding.Convert(Encoding.Unicode, targetEnc, Encoding.Unicode.GetBytes(src));
            string dest = targetEnc.GetString(bytes);
            Row.NonUnicodeCol = dest;
catch (EncoderFallbackException e)
// Log the problematic row ID for later analysis
            ComponentMetaData.FireError(0, "UnicodeConversion",
                $"Row Row.RowNumber: cannot encode character(s) – e.Message", "", 0, out bool cancel);
            // Decide: drop row, set to empty, or copy as is with placeholder
            Row.NonUnicodeCol = string.Empty;

| Fix type | When to use | What to do | |----------|------------|------------| | Refresh the component | Schema changed in source, same environment | Right‑click the component → Refresh (or click Validate). This forces SSIS to re‑pull the external metadata. | | Re‑configure the component | Column added/removed, data‑type change | Open the component → Columns tab → remove the old column, add the new one, or adjust the data‑type mapping. | | Update downstream components | Any change cascades to downstream components (e.g., OLE DB Destination, Derived Column) | Repeat the Refresh on each downstream component; if column names change, you may need to re‑map them. | | Use explicit column list instead of SELECT * | Dynamic queries cause hidden drift | Change the source query to list the columns explicitly, e.g., SELECT ColumnA, ColumnB FROM dbo.SampleTable. | | Add a Data Conversion component | Source type changed to a larger type that downstream components cannot handle (e.g., bigint → int) | Convert the column to the expected type before it reaches the failing component. | | Parameterize the query properly | Query built with expressions that may change the schema | Ensure the expression always returns the same column list, or move the query logic to a stored procedure with a stable result set. | | Re‑deploy the package after a full validation | Corrupted metadata cache | In SSDT, right‑click the project → Build → Deploy. Make sure the target server has the latest package version. | | Create a new connection manager (if connection string changed) | Different server/DB version (e.g., SQL 2008 → SQL 2019) | Delete the old connection manager, add a new one, and re‑wire the components. | SSIS-661

| Technique | How to implement | |-----------|-----------------| | Schema validation at the start of the package | Add an Execute SQL Task that runs SELECT TOP 0 * FROM dbo.Table and checks sys.columns via a script task; raise an error if a mismatch is detected. | | Version‑controlled source objects | Keep a DDL script in source control and enforce a build‑time check that the production object matches the script. | | Explicit column list in all sources | Never use SELECT *. | | Package‑level data‑type constraints | Use the Data Flow → Advanced → Data Type property to lock a column to a specific type. | | Deploy with “ValidateExternalMetadata = False” (cautiously) | In scenarios where you know the schema will change but you want the package to continue, set the property on the component, but be aware you lose early detection. | | Continuous Integration (CI) testing | Add a step in your CI pipeline that runs the package against a test copy of the production database and fails the build on any SSIS‑661 (or other) error. | If you must stay with a non‑Unicode destination,