/// <summary>
/// Construct a SchemaChange event, used when parsing DDL events
/// </summary>
/// <param name="ddeID">Pointer to ddl event ID generated on the master</param>
/// <param name="eventType">The type of event (i.e. Add, Drop, Modify, Rename a column)</param>
/// <param name="schemaName">Database table schema name (i.e. dbo)</param>
/// <param name="tableName">Table the change applies to</param>
/// <param name="columnName">Column the change applies to </param>
/// <param name="newColumnName">New column name (for rename events only)</param>
/// <param name="dataType">Data type of the column (for modify/add events only)</param>
public SchemaChange(int ddeID, SchemaChangeType eventType, string schemaName, string tableName, string columnName, string newColumnName, DataType dataType = null)
{
this.DdeID = ddeID;
this.EventType = eventType;
this.SchemaName = schemaName;
this.TableName = tableName;
this.ColumnName = columnName;
this.NewColumnName = newColumnName;
this.DataType = dataType;
}
/// <summary>
/// Constructor used on the slave side when reading published schema change events
/// </summary>
/// <param name="row">DataRow from querying schema change table</param>
public SchemaChange(DataRow row)
{
DdeID = row.Field<int>("CscDdeID");
EventType = (SchemaChangeType)Enum.Parse(typeof(SchemaChangeType), row.Field<string>("CscEventType"));
SchemaName = row.Field<string>("CscSchema");
TableName = row.Field<string>("CscTableName");
ColumnName = row.Field<string>("CscColumnName");
NewColumnName = row.Field<string>("CscNewColumnName");
DataType = new DataType(row.Field<string>("CscBaseDataType"), row.Field<int?>("CscCharacterMaximumLength"),
row.Field<int?>("CscNumericPrecision"), row.Field<int?>("CscNumericScale"));
}
/// <summary>
/// Compare two DataType objects that may both be null. Used for unit tests
/// </summary>
/// <param name="expected">Expected data type</param>
/// <param name="actual">Actual data type</param>
/// <returns>True if the objects are equal or both null</returns>
public static bool Equals(DataType expected, DataType actual)
{
if (expected == null && actual == null) {
return true;
}
if (expected == null || actual == null) {
return false;
}
if (expected.BaseType != actual.BaseType
|| expected.CharacterMaximumLength != actual.CharacterMaximumLength
|| expected.NumericPrecision != actual.NumericPrecision
|| expected.NumericScale != actual.NumericScale
) {
return false;
}
return true;
}