public Task <IEnumerable <object> > GetAsync(
IHaveSelectionSet context,
EntityMetadataContext metadata)
{
return(Task.FromResult(Enumerable.Range(1, 10).Select(e =>
{
var instance = Activator.CreateInstance(metadata.Type);
return instance;
})));
}
public static EntityMetadataContext <T> Schema <T>(this EntityMetadataContext <T> context, string schemaName)
{
context.CustomMetadata.Add(Globals.CUSTOM_METADATA_SCHEMA, schemaName);
return(context);
}
public static EntityMetadataContext <T> Table <T>(this EntityMetadataContext <T> context, string tableName)
{
context.CustomMetadata.Add(Globals.CUSTOM_METADATA_TABLE, tableName);
return(context);
}
private static SqlGenerationContext GenerateSQL(
IHaveSelectionSet context,
EntityMetadataContext metadata,
SqlGenerationContext sqlContext = null,
SQLOperation operation = SQLOperation.SELECT,
int level = 0,
string parentAlias = null,
EntityMetadataRelation relationMetadata = null)
{
if (sqlContext == null)
{
sqlContext = new SqlGenerationContext();
}
var key = metadata.Keys.Values.ToArray();
var schema =
metadata.CustomMetadata.TryGetValue(Globals.CUSTOM_METADATA_SCHEMA, out var customSchema) ?
customSchema : "dbo";
var table =
metadata.CustomMetadata.TryGetValue(Globals.CUSTOM_METADATA_TABLE, out var customTable) ?
customTable : metadata.Type.Name;
var queriedFields = context.GetSelectedFields();
var alias = GetAlias(level);
var entityFields =
metadata.Included.Keys
.Select(f => f.ToLower())
.Intersect(queriedFields.Keys)
.Select(f => new { field = $"{f}", exp = $"{alias}.[{f}]" })
.ToArray();
sqlContext.SelectFields.AddRange(entityFields);
sqlContext.SplitOnTypes.Add(metadata.Type);
if (level > 0)
{
sqlContext.SplitOnFields.Add(entityFields.First().field);
}
if (operation == SQLOperation.SELECT)
{
sqlContext.Sql = $"SELECT %fields% FROM [{schema}].[{table}] {alias}";
foreach (var field in queriedFields)
{
if (metadata.Relations.TryGetValue(field.Key.ToLower(), out var relation))
{
sqlContext.Relations.Add(relation);
GenerateSQL(
field.Value,
relation.EntityRight,
sqlContext,
operation: SQLOperation.JOIN,
level: level + 1,
parentAlias: alias,
relationMetadata: relation
);
}
}
}
else if (operation == SQLOperation.JOIN)
{
if (relationMetadata.IsCollection)
{
sqlContext.Sql += $" LEFT JOIN [{schema}].[{table}] {alias} ON {ManyForeignKeyCriteria(parentAlias, alias, relationMetadata)}";
}
else
{
sqlContext.Sql += $" LEFT JOIN [{schema}].[{table}] {alias} ON {SingleForeignKeyCriteria(parentAlias, alias, relationMetadata)}";
}
}
if (level == 0)
{
sqlContext.Sql = sqlContext.Sql.Replace("%fields%", string.Join(",", sqlContext.SelectFields.Select(x => x.exp)));
}
return(sqlContext);
}
public async Task <IEnumerable <dynamic> > GetAsync(
IHaveSelectionSet context,
EntityMetadataContext metadata)
{
using (var connection = connectionFactory())
{
var sql = GenerateSQL(context, metadata);
HashSet <object>[] mapping =
Enumerable.Range(1, sql.SplitOnTypes.Count())
.Select(x => new HashSet <object>())
.ToArray();
List <dynamic>[] objectCache =
Enumerable.Range(1, sql.SplitOnTypes.Count())
.Select(x => new List <dynamic>())
.ToArray();
object[] lastEntities = new dynamic[sql.SplitOnTypes.Count()];
(await connection.QueryAsync <dynamic>(
sql.Sql,
sql.SplitOnTypes.ToArray(),
splitOn: string.Join(",", sql.SplitOnFields),
map: (entities) =>
{
object result = entities[0];
int i = 0;
foreach (var entity in entities)
{
var entityKey =
i == 0 ?
metadata.PrimaryKey(entity) :
sql.Relations[i - 1].EntityRight.PrimaryKey(entity);
if (mapping[i].Contains(entityKey))
{
if (i == 0)
{
result = null;
}
}
else
{
if (lastEntities[i] != null)
{
if (i < objectCache.Length - 1)
{
foreach (var obj in objectCache[i + 1])
{
if (sql.Relations[i].IsCollection)
{
sql.Relations[i].Add(lastEntities[i], obj);
}
else
{
sql.Relations[i].Set(lastEntities[i], obj);
}
}
objectCache[i + 1].Clear();
mapping[i + 1].Clear();
}
}
objectCache[i].Add(entity);
mapping[i].Add(entityKey);
lastEntities[i] = entity;
}
i++;
}
return(result);
}
)).ToArray();
int idx = 0;
foreach (var entity in lastEntities)
{
if (entity != null)
{
if (idx < objectCache.Length - 1)
{
foreach (var obj in objectCache[idx + 1])
{
if (sql.Relations[idx].IsCollection)
{
sql.Relations[idx].Add(entity, obj);
}
else
{
sql.Relations[idx].Set(entity, obj);
}
}
objectCache[idx + 1].Clear();
}
}
idx++;
}
return(objectCache[0]);
}
}
