/// <summary>
/// For a given UnitOfWorkContext, perform a schema upgrade if necessary. The ordered set of revisions are executed from version+1 to version[n].
/// </summary>
/// <param name="unitOfWorkContext"> The target UnitOfWorkContext. </param>
/// <returns> A value indicating whether any changes were needed against the target database (file). </returns>
public bool PerformSchemaUpgrade(IUnitOfWorkContext unitOfWorkContext)
{
bool changed = false;
DatabaseRevision revision;
string svalue;
int ivalue;
int schemaRevision, currentSchemaRevision, recordsAffected;
IList<IDictionary<string, object>> results;
if ((object)unitOfWorkContext == null)
throw new ArgumentNullException("unitOfWorkContext");
if (this.Revisions.Count < 1)
throw new InvalidOperationException("TODO (enhancement): add meaningful message");
ivalue = unitOfWorkContext.FetchScalar<int>(CommandType.Text, this.DoesSchemaTrackingExistCommandText, null);
if (ivalue != 1)
{
// revision -1
schemaRevision = -1;
}
else
{
svalue = unitOfWorkContext.FetchScalar<string>(CommandType.Text, this.GetSchemaVersionCommandText, null);
if (!DataType.TryParse(svalue, out schemaRevision))
throw new InvalidOperationException("TODO (enhancement): add meaningful message");
}
currentSchemaRevision = this.Revisions.Max(x => x.Number);
if (schemaRevision != currentSchemaRevision)
{
changed = true;
for (int workingRevision = schemaRevision + 1; workingRevision <= currentSchemaRevision; workingRevision++)
{
int _workingRevision = workingRevision;
revision = this.Revisions.SingleOrDefault(rh => rh.Number == _workingRevision);
if ((object)revision == null)
throw new InvalidOperationException(String.Format("The revision number '{0}' was not found. Revsions must be sequential without any gaps.", _workingRevision));
if (revision.Statements.Count < 1)
throw new InvalidOperationException("A revsion must have at least one statement.");
foreach (string statement in revision.Statements)
unitOfWorkContext.ExecuteDictionary(CommandType.Text, statement, null, out recordsAffected);
results = unitOfWorkContext.ExecuteDictionary(CommandType.Text, this.IncrementSchemaVersionCommandText, null, out recordsAffected);
if (recordsAffected != 1)
throw new InvalidOperationException("TODO (enhancement): add meaningful message");
}
}
ivalue = unitOfWorkContext.FetchScalar<int>(CommandType.Text, this.DoesSchemaTrackingExistCommandText, null);
if (ivalue != 1)
throw new InvalidOperationException("TODO (enhancement): add meaningful message");
svalue = unitOfWorkContext.FetchScalar<string>(CommandType.Text, this.GetSchemaVersionCommandText, null);
if (!DataType.TryParse(svalue, out schemaRevision))
throw new InvalidOperationException("TODO (enhancement): add meaningful message");
if (schemaRevision != currentSchemaRevision)
throw new InvalidOperationException("TODO (enhancement): add meaningful message");
return changed;
}