/// <summary>
/// Generates a delete core command for the given entity, or returns null if such
/// command cannot be generated for whatever reasons.
/// </summary>
internal static IDeleteCommand GenerateDeleteCommand(this IUberMap map, object entity)
{
if (entity == null)
{
return(null);
}
if (map == null || map.IsDisposed || !map.IsValidated)
{
return(null);
}
IDeleteCommand cmd = null;
MetaEntity meta = MetaEntity.Locate(entity, create: true); if (meta.Record == null)
{
var record = new Core.Concrete.Record(map.Schema);
map.WriteRecord(entity, record);
meta.Record = record;
}
var id = map.ExtractId(meta.Record);
if (id != null)
{
cmd = map.Link.Engine.CreateDeleteCommand(map.Link, x => map.Table);
if (map.Discriminator != null)
{
cmd.Where(map.Discriminator);
}
var tag = new DynamicNode.Argument("x");
for (int i = 0; i < id.Count; i++)
{
var left = new DynamicNode.GetMember(tag, id.Schema[i].ColumnName);
var bin = new DynamicNode.Binary(left, ExpressionType.Equal, id[i]);
cmd.Where(x => bin);
left.Dispose();
bin.Dispose();
}
tag.Dispose();
id.Dispose();
}
return(cmd);
}
/// <summary>
/// Validates that the row version captured in the meta-entity is the same as the current
/// one in the database, throwing an exception if a change is detected.
/// </summary>
internal static void ValidateRowVersion(this MetaEntity meta)
{
var entity = meta.Entity; if (entity == null)
{
return;
}
if (meta.UberMap == null)
{
return;
}
if (meta.Record == null)
{
return;
}
var vc = meta.UberMap.VersionColumn;
if (vc.Name == null)
{
return;
}
// Getting the most updated record, if any...
var cmd = meta.UberMap.Link.From(x => meta.UberMap.Table);
var tag = new DynamicNode.Argument("x");
var id = meta.UberMap.ExtractId(meta.Record);
if (id == null)
{
throw new InvalidOperationException(
"Cannot obtain identity from entity '{0}'".FormatWith(meta));
}
for (int i = 0; i < id.Count; i++)
{
var left = new DynamicNode.GetMember(tag, id.Schema[i].ColumnName);
var bin = new DynamicNode.Binary(left, ExpressionType.Equal, id[i]);
cmd.Where(x => bin);
bin.Dispose();
left.Dispose();
}
id.Dispose();
tag.Dispose();
var rec = (IRecord)cmd.First();
cmd.Dispose();
if (rec == null)
{
return;
}
// Comparing values....
string captured = vc.ValueToString == null
? meta.Record[vc.Name].Sketch()
: vc.ValueToString(meta.Record[vc.Name]);
string current = vc.ValueToString == null
? rec[vc.Name].Sketch()
: vc.ValueToString(rec[vc.Name]);
if (string.Compare(captured, current) != 0)
{
throw new ChangedException(
"Captured version '{0}' for entity '{1}' differs from the database's current one '{2}'."
.FormatWith(captured, meta, current));
}
}
/// <summary>
/// Generates an update core command for the given entity, or returns null if such
/// command cannot be generated for whatever reasons.
/// </summary>
internal static IUpdateCommand GenerateUpdateCommand(this IUberMap map, object entity)
{
if (entity == null)
{
return(null);
}
if (map == null || map.IsDisposed || !map.IsValidated)
{
return(null);
}
IUpdateCommand cmd = null;
MetaEntity meta = MetaEntity.Locate(entity, create: true); if (meta.Record == null)
{
var record = new Core.Concrete.Record(map.Schema);
map.WriteRecord(entity, record);
meta.Record = record;
}
var changes = meta.GetRecordChanges(); if (changes == null)
{
return(null);
}
var num = changes.Schema.Count(x => !x.IsReadOnlyColumn);
if (num != 0)
{
var id = map.ExtractId(meta.Record); if (id != null)
{
cmd = map.Link.Engine.CreateUpdateCommand(map.Link, x => map.Table);
if (map.Discriminator != null)
{
cmd.Where(map.Discriminator);
}
var tag = new DynamicNode.Argument("x");
for (int i = 0; i < id.Count; i++)
{
var left = new DynamicNode.GetMember(tag, id.Schema[i].ColumnName);
var bin = new DynamicNode.Binary(left, ExpressionType.Equal, id[i]);
cmd.Where(x => bin);
left.Dispose();
bin.Dispose();
}
for (int i = 0; i < changes.Count; i++)
{
if (changes.Schema[i].IsReadOnlyColumn)
{
continue;
}
var node = new DynamicNode.SetMember(tag, changes.Schema[i].ColumnName, changes[i]);
cmd.Columns(x => node);
node.Dispose();
}
tag.Dispose();
id.Dispose();
}
}
changes.Dispose(disposeSchema: true);
return(cmd);
}