diff --git a/dlls/msi/streams.c b/dlls/msi/streams.c
index 9828b7f355c..995027057a6 100644
--- a/dlls/msi/streams.c
+++ b/dlls/msi/streams.c
@@ -54,9 +54,9 @@ typedef struct tagMSISTREAMSVIEW
     UINT row_size;
 } MSISTREAMSVIEW;
 
-static BOOL add_stream_to_table(MSISTREAMSVIEW *sv, STREAM *stream, int index)
+static BOOL streams_set_table_size(MSISTREAMSVIEW *sv, int size)
 {
-    if (index >= sv->max_streams)
+    if (size >= sv->max_streams)
     {
         sv->max_streams *= 2;
         sv->streams = msi_realloc(sv->streams, sv->max_streams * sizeof(STREAM *));
@@ -64,7 +64,6 @@ static BOOL add_stream_to_table(MSISTREAMSVIEW *sv, STREAM *stream, int index)
             return FALSE;
     }
 
-    sv->streams[index] = stream;
     return TRUE;
 }
 
@@ -139,12 +138,6 @@ static UINT STREAMS_get_row( struct tagMSIVIEW *view, UINT row, MSIRECORD **rec
 }
 
 static UINT STREAMS_set_row(struct tagMSIVIEW *view, UINT row, MSIRECORD *rec, UINT mask)
-{
-    FIXME("(%p, %d, %p, %d): stub!\n", view, row, rec, mask);
-    return ERROR_SUCCESS;
-}
-
-static UINT STREAMS_insert_row(struct tagMSIVIEW *view, MSIRECORD *rec, BOOL temporary)
 {
     MSISTREAMSVIEW *sv = (MSISTREAMSVIEW *)view;
     STREAM *stream;
@@ -156,7 +149,10 @@ static UINT STREAMS_insert_row(struct tagMSIVIEW *view, MSIRECORD *rec, BOOL tem
     ULONG count;
     UINT r = ERROR_FUNCTION_FAILED;
 
-    TRACE("(%p, %p, %d)\n", view, rec, temporary);
+    TRACE("(%p, %p)\n", view, rec);
+
+    if (row > sv->num_rows)
+        return ERROR_FUNCTION_FAILED;
 
     r = MSI_RecordGetIStream(rec, 2, &stm);
     if (r != ERROR_SUCCESS)
@@ -201,8 +197,7 @@ static UINT STREAMS_insert_row(struct tagMSIVIEW *view, MSIRECORD *rec, BOOL tem
     IStorage_OpenStream(sv->db->storage, name, 0,
                         STGM_READ | STGM_SHARE_EXCLUSIVE, 0, &stream->stream);
 
-    if (!add_stream_to_table(sv, stream, sv->num_rows++))
-        goto done;
+    sv->streams[row] = stream;
 
 done:
     msi_free(name);
@@ -213,6 +208,16 @@ done:
     return r;
 }
 
+static UINT STREAMS_insert_row(struct tagMSIVIEW *view, MSIRECORD *rec, BOOL temporary)
+{
+    MSISTREAMSVIEW *sv = (MSISTREAMSVIEW *)view;
+
+    if (!streams_set_table_size(sv, ++sv->num_rows))
+        return ERROR_FUNCTION_FAILED;
+
+    return STREAMS_set_row(view, sv->num_rows - 1, rec, 0);
+}
+
 static UINT STREAMS_delete_row(struct tagMSIVIEW *view, UINT row)
 {
     FIXME("(%p %d): stub!\n", view, row);
@@ -278,6 +283,52 @@ static UINT STREAMS_get_column_info(struct tagMSIVIEW *view,
     return ERROR_SUCCESS;
 }
 
+static UINT streams_find_row(MSISTREAMSVIEW *sv, MSIRECORD *rec, UINT *row)
+{
+    LPCWSTR str;
+    UINT i, id, data;
+
+    str = MSI_RecordGetString(rec, 1);
+    msi_string2idW(sv->db->strings, str, &id);
+
+    for (i = 0; i < sv->num_rows; i++)
+    {
+        STREAMS_fetch_int(&sv->view, i, 1, &data);
+
+        if (data == id)
+        {
+            *row = i;
+            return ERROR_SUCCESS;
+        }
+    }
+
+    return ERROR_FUNCTION_FAILED;
+}
+
+static UINT streams_modify_update(struct tagMSIVIEW *view, MSIRECORD *rec)
+{
+    MSISTREAMSVIEW *sv = (MSISTREAMSVIEW *)view;
+    UINT r, row;
+
+    r = streams_find_row(sv, rec, &row);
+    if (r != ERROR_SUCCESS)
+        return ERROR_FUNCTION_FAILED;
+
+    return STREAMS_set_row(view, row, rec, 0);
+}
+
+static UINT streams_modify_assign(struct tagMSIVIEW *view, MSIRECORD *rec)
+{
+    MSISTREAMSVIEW *sv = (MSISTREAMSVIEW *)view;
+    UINT r, row;
+
+    r = streams_find_row(sv, rec, &row);
+    if (r == ERROR_SUCCESS)
+        return streams_modify_update(view, rec);
+
+    return STREAMS_insert_row(view, rec, FALSE);
+}
+
 static UINT STREAMS_modify(struct tagMSIVIEW *view, MSIMODIFY eModifyMode, MSIRECORD *rec, UINT row)
 {
     UINT r;
@@ -286,15 +337,21 @@ static UINT STREAMS_modify(struct tagMSIVIEW *view, MSIMODIFY eModifyMode, MSIRE
 
     switch (eModifyMode)
     {
+    case MSIMODIFY_ASSIGN:
+        r = streams_modify_assign(view, rec);
+        break;
+
     case MSIMODIFY_INSERT:
         r = STREAMS_insert_row(view, rec, FALSE);
         break;
 
+    case MSIMODIFY_UPDATE:
+        r = streams_modify_update(view, rec);
+        break;
+
     case MSIMODIFY_VALIDATE_NEW:
     case MSIMODIFY_INSERT_TEMPORARY:
-    case MSIMODIFY_UPDATE:
     case MSIMODIFY_REFRESH:
-    case MSIMODIFY_ASSIGN:
     case MSIMODIFY_REPLACE:
     case MSIMODIFY_MERGE:
     case MSIMODIFY_DELETE:
@@ -425,11 +482,13 @@ static UINT add_streams_to_table(MSISTREAMSVIEW *sv)
                             STGM_READ | STGM_SHARE_EXCLUSIVE, 0, &stream->stream);
         CoTaskMemFree(stat.pwcsName);
 
-        if (!add_stream_to_table(sv, stream, count++))
+        if (!streams_set_table_size(sv, ++count))
         {
             count = -1;
             break;
         }
+
+        sv->streams[count - 1] = stream;
     }
 
     IEnumSTATSTG_Release(stgenum);