mcs/class/System.Data/System.Data/MergeManager.cs

   1 using System;\r
   2 \r
   3 namespace System.Data\r
   4 {\r
   5         /// <summary>\r
   6         /// Summary description for MergeManager.\r
   7         /// </summary>\r
   8         internal class MergeManager\r
   9         {\r
  10                 internal static void Merge(DataSet targetSet, DataSet sourceSet, bool preserveChanges, MissingSchemaAction missingSchemaAction)\r
  11                 {\r
  12                         if(targetSet == null)\r
  13                                 throw new ArgumentNullException("targetSet");\r
  14                         if(sourceSet == null)\r
  15                                 throw new ArgumentNullException("sourceSet");\r
  16 \r
  17                         foreach (DataTable t in sourceSet.Tables)\r
  18                                 MergeManager.Merge(targetSet, t, preserveChanges, missingSchemaAction);\r
  19 \r
  20                 }\r
  21 \r
  22                 internal static void Merge(DataSet targetSet, DataTable sourceTable, bool preserveChanges, MissingSchemaAction missingSchemaAction)\r
  23                 {\r
  24                         if(targetSet == null)\r
  25                                 throw new ArgumentNullException("targetSet");\r
  26                         if(sourceTable == null)\r
  27                                 throw new ArgumentNullException("sourceTable");\r
  28 \r
  29                         \r
  30                         if (!AdjustSchema(targetSet, sourceTable, missingSchemaAction))\r
  31                                 return;\r
  32                         DataTable targetTable = targetSet.Tables[sourceTable.TableName];\r
  33                         if (targetTable != null)\r
  34                         {\r
  35                                 checkColumnTypes(targetTable, sourceTable); // check that the colums datatype is the same\r
  36                                 fillData(targetTable, sourceTable, preserveChanges);\r
  37                         }\r
  38                         \r
  39                 }\r
  40 \r
  41                 internal static void Merge(DataSet targetSet, DataRow[] sourceRows, bool preserveChanges, MissingSchemaAction missingSchemaAction)\r
  42                 {\r
  43                         if(targetSet == null)\r
  44                                 throw new ArgumentNullException("targetSet");\r
  45                         if(sourceRows == null)\r
  46                                 throw new ArgumentNullException("sourceRows");\r
  47 \r
  48                         for (int i = 0; i < sourceRows.Length; i++)\r
  49                         {\r
  50                                 DataRow row = sourceRows[i];\r
  51                                 DataTable sourceTable = row.Table;\r
  52                                 if (!AdjustSchema(targetSet, sourceTable, missingSchemaAction))\r
  53                                         return;\r
  54                                 DataTable targetTable = targetSet.Tables[row.Table.TableName];\r
  55                                 if (targetTable != null)\r
  56                                 {\r
  57                                         checkColumnTypes(targetTable, row.Table);\r
  58                                         MergeRow(targetTable, row, preserveChanges);\r
  59                                 }\r
  60                         }\r
  61                 }\r
  62 \r
  63                 // merge a row into a target table.\r
  64                 private static void MergeRow(DataTable targetTable, DataRow row, bool preserveChanges)\r
  65                 {\r
  66                         DataColumnCollection columns = row.Table.Columns;\r
  67                         DataColumn[] primaryKeys = targetTable.PrimaryKey;\r
  68                         DataRow targetRow = null;\r
  69                         DataRowVersion version = DataRowVersion.Default;\r
  70                         if (row.RowState == DataRowState.Deleted)\r
  71                                 version = DataRowVersion.Original;\r
  72 \r
  73                         if (primaryKeys != null && primaryKeys.Length > 0) // if there are any primary key.\r
  74                         {\r
  75                                 // initiate an array that has the values of the primary keys.\r
  76                                 object[] keyValues = new object[primaryKeys.Length];\r
  77                                 \r
  78                                 for (int j = 0; j < keyValues.Length; j++)\r
  79                                 {\r
  80                                         keyValues[j] = row[primaryKeys[j].ColumnName, version];\r
  81                                 }\r
  82                         \r
  83                                 // find the row in the target table.\r
  84                                 targetRow = targetTable.Rows.Find(keyValues);\r
  85                         }\r
  86                         // row doesn't exist in target table, or there are no primary keys.\r
  87                         // create new row and copy values from source row to the new row.\r
  88                         if (targetRow == null)\r
  89                         { \r
  90                                 targetRow = targetTable.NewRow();\r
  91                                 row.CopyValuesToRow(targetRow);\r
  92                                 targetTable.Rows.Add(targetRow);\r
  93                         }\r
  94                         // row exists in target table, and presere changes is false - \r
  95                         // change the values of the target row to the values of the source row.\r
  96                         else if (!preserveChanges)\r
  97                         {\r
  98                                 row.CopyValuesToRow(targetRow);\r
  99                         }\r
 100 \r
 101                 }\r
 102                         \r
 103                 \r
 104                 \r
 105                 // adjust the table schema according to the missingschemaaction param.\r
 106                 // return false if adjusting fails.\r
 107                 private static bool AdjustSchema(DataSet targetSet, DataTable sourceTable, MissingSchemaAction missingSchemaAction)\r
 108                 {\r
 109                         string tableName = sourceTable.TableName;\r
 110                         \r
 111                         // if the source table not exists in the target dataset\r
 112                         // we act according to the missingschemaaction param.\r
 113                         if (!targetSet.Tables.Contains(tableName))\r
 114                         {\r
 115                                 if (missingSchemaAction == MissingSchemaAction.Ignore)\r
 116                                         return true;\r
 117                                 if (missingSchemaAction == MissingSchemaAction.Error)\r
 118                                         throw new ArgumentException("Target DataSet missing definition for "+ tableName + ".");\r
 119                                 targetSet.Tables.Add((DataTable)sourceTable.Clone());\r
 120                         }\r
 121                         \r
 122                         DataTable table = targetSet.Tables[tableName];\r
 123                         \r
 124                         if (!CheckPrimaryKeys(table, sourceTable))\r
 125                                 return false;\r
 126                         \r
 127                         for (int i = 0; i < sourceTable.Columns.Count; i++)\r
 128                         {\r
 129                                 DataColumn col = sourceTable.Columns[i];\r
 130                                 // if a column from the source table doesn't exists in the target table\r
 131                                 // we act according to the missingschemaaction param.\r
 132                                 if(!table.Columns.Contains(col.ColumnName))\r
 133                                 {\r
 134                                         if (missingSchemaAction == MissingSchemaAction.Ignore)\r
 135                                                 continue;\r
 136                                         if (missingSchemaAction == MissingSchemaAction.Error)\r
 137                                                 throw new ArgumentException(("Column '" + col.ColumnName + "' does not belong to table Items."));\r
 138                                         \r
 139                                         table.Columns.Add(new DataColumn(col.ColumnName, col.DataType, col.Expression, col.ColumnMapping));\r
 140                                 }\r
 141                         }\r
 142 \r
 143                         return true;\r
 144                 }\r
 145                 \r
 146                 // find if there is a valid matching between the targetTable PrimaryKey and the\r
 147                 // sourceTable primatyKey.\r
 148                 // return true if there is a match, else return false and raise a MergeFailedEvent.\r
 149                 private static bool CheckPrimaryKeys(DataTable targetTable, DataTable sourceTable)\r
 150                 {\r
 151                         // if the length of one of the tables primarykey if 0 - there is nothing to check.\r
 152                         if (targetTable.PrimaryKey.Length != 0 && sourceTable.PrimaryKey.Length != 0)\r
 153                         {\r
 154                                 // if the length of primarykey is not equal - merge fails\r
 155                                 if (targetTable.PrimaryKey.Length != sourceTable.PrimaryKey.Length)\r
 156                                 {\r
 157                                         string message = "<target>.PrimaryKey and <source>.PrimaryKey have different Length.";\r
 158                                         MergeFailedEventArgs e = new MergeFailedEventArgs(sourceTable, message);\r
 159                                         targetTable.DataSet.OnMergeFailed(e);\r
 160                                         return false;\r
 161                                 }\r
 162                                 else\r
 163                                 {\r
 164                                         // we have to see that each primary column in the target table\r
 165                                         // has a column with the same name in the sourcetable primarykey columns. \r
 166                                         bool foundMatch;\r
 167                                         DataColumn[] targetDataColumns = targetTable.PrimaryKey;\r
 168                                         DataColumn[] srcDataColumns = sourceTable.PrimaryKey;\r
 169 \r
 170                                         // loop on all primary key columns in the targetTable.\r
 171                                         for (int i = 0; i < targetDataColumns.Length; i++)\r
 172                                         {\r
 173                                                 foundMatch = false;\r
 174                                                 DataColumn col = targetDataColumns[i];\r
 175 \r
 176                                                 // find if there is a column with the same name in the \r
 177                                                 // sourceTable primary key columns.\r
 178                                                 for (int j = 0; j < srcDataColumns.Length; j++)\r
 179                                                 {\r
 180                                                         if (srcDataColumns[j].ColumnName == col.ColumnName)\r
 181                                                         {\r
 182                                                                 foundMatch = true;\r
 183                                                                 break;\r
 184                                                         }\r
 185                                                 }\r
 186                                                 if (!foundMatch)\r
 187                                                 {\r
 188                                                         string message = "Mismatch columns in the PrimaryKey : <target>." + col.ColumnName + " versus <source>." + srcDataColumns[i].ColumnName + ".";\r
 189                                                         MergeFailedEventArgs e = new MergeFailedEventArgs(sourceTable, message);\r
 190                                                         targetTable.DataSet.OnMergeFailed(e);\r
 191                                                         return false;\r
 192                                                 }\r
 193                                                 \r
 194                                         }\r
 195                                 }\r
 196                         }\r
 197 \r
 198                         return true;\r
 199                 }\r
 200                 \r
 201                 // fill the data from the source table to the target table\r
 202                 private static void fillData(DataTable targetTable, DataTable sourceTable, bool preserveChanges)\r
 203                 {\r
 204                         for (int i = 0; i < sourceTable.Rows.Count; i++)\r
 205                         {\r
 206                                 DataRow row = sourceTable.Rows[i];\r
 207                                 MergeRow(targetTable, row, preserveChanges);\r
 208                         }\r
 209                 }\r
 210                 \r
 211                 // check tha column from 2 tables that has the same name also has the same datatype.\r
 212                 private static void checkColumnTypes(DataTable targetTable, DataTable sourceTable)\r
 213                 {\r
 214                         for (int i = 0; i < sourceTable.Columns.Count; i++)\r
 215                         {\r
 216                                 DataColumn fromCol = sourceTable.Columns[i];\r
 217                                 DataColumn toCol = targetTable.Columns[fromCol.ColumnName];\r
 218                                 if((toCol != null) && (toCol.DataType != fromCol.DataType))\r
 219                                         throw new DataException("<target>." + fromCol.ColumnName + " and <source>." + fromCol.ColumnName + " have conflicting properties: DataType property mismatch.");\r
 220                         }\r
 221                 }\r
 222         }\r
 223 }\r