/// <summary>
/// Generate the expression to use in the SELECT clause. For regular columns this is just the column name. For left-joined
/// columns, this is a sub-select statement.
/// </summary>
/// <param name="dbdef"></param>
/// <param name="tabledef"></param>
/// <param name="coldef"></param>
/// <returns></returns>
protected virtual string SqlColumnExpression(DataDictionary dbdef, TableDef tabledef, ColDef coldef)
{
//auto-left-joined col
if (coldef.LeftJoin != null)
{
var fkCol = tabledef.FindCol(coldef.LeftJoin.ForeignKeyColumnName);
if (fkCol == null)
{
throw new Exception($"Invalid foreign key column name in LeftJoin info on {coldef.Name}; it must be the name of a column in the same table");
}
if (fkCol.ForeignKeyDatonTypeName == null)
{
throw new Exception($"Invalid use of foreign key column in LeftJoin; {fkCol.Name} must use a ForeignKey annotation to identify the foriegn table");
}
var foreignTabledef = dbdef.FindDef(fkCol.ForeignKeyDatonTypeName).MainTableDef;
string tableAlias = "_t_" + (++MaxtDynamicAliasUsed);
return($"(select {coldef.LeftJoin.RemoteDisplayColumnName} from {foreignTabledef.SqlTableName} {tableAlias} where {tableAlias}.{foreignTabledef.PrimaryKeyColName}={tabledef.SqlTableName}.{fkCol.Name})");
}
if (coldef.IsCustom || coldef.IsComputed)
{
throw new Exception("Cannot load custom or computed column from database");
}
//regular col
return(coldef.Name);
}
/// <summary>
/// Get where clause for viewon main table
/// </summary>
protected virtual SqlSelectBuilder.Where MainTableWhereClause(TableDef tabledef, ViewonKey key)
{
var w = new SqlSelectBuilder.Where();
foreach (var cri in key.Criteria)
{
var coldef = tabledef.FindCol(cri.Name);
if (coldef != null)
{
var crihelper = new ViewonCriterion(coldef, cri.PackedValue);
crihelper.ExportWhereClause(w, SqlFlavor);
}
}
return(w);
}
/// <summary>
/// Get where clause for persiston main table, or null if this is a whole-table persiston
/// </summary>
protected virtual SqlSelectBuilder.Where MainTableWhereClause(TableDef tabledef, PersistonKey key)
{
if (key.WholeTable)
{
return(null);
}
var pkType = tabledef.FindCol(tabledef.PrimaryKeyColName).CSType;
object pk = key.PrimaryKey; //always string here
if (pkType != typeof(string))
{
pk = Utils.ChangeType(pk, pkType);
}
var w = new SqlSelectBuilder.Where();
w.AddWhere($"{tabledef.PrimaryKeyColName}={w.NextParameterName()}", pk);
return(w);
}
/// <summary>
/// Look for array nodes matching tableDef, such as Customer, Customer-new, Customer-deleted; and then
/// construct target rows based on the values found in those arrays
/// </summary>
private static void ReadJsonDiffRowArray(JObject parent, TableDef tableDef, List <PersistonDiff.DiffRow> targetA)
{
void ParseArray(string arrayName, DiffKind kind, bool allowChildren, bool fillInMissingNegativeKey)
{
var rows = parent[arrayName];
if (rows == null)
{
return;
}
if (!(rows is JArray rowsA))
{
throw new Exception($"Diff json nodes must be arrays");
}
foreach (var childNode in rowsA)
{
if (!(childNode is JObject childObject))
{
throw new Exception("Diff array members must be row objects, not values or arrays");
}
var target = new PersistonDiff.DiffRow()
{
Kind = kind
};
targetA.Add(target);
ReadJsonDiffRow(childObject, target, tableDef, allowChildren);
//if the client omits -1 primary key value on new rows, add it here; the save logic needs it but it is redundant from the client perspective
if (fillInMissingNegativeKey && !target.Columns.ContainsKey(tableDef.PrimaryKeyColName))
{
var newRowPK = Utils.ChangeType(-1, tableDef.FindCol(tableDef.PrimaryKeyColName).CSType);
target.Columns[tableDef.PrimaryKeyColName] = newRowPK;
}
}
}
string name = CamelCasify(tableDef.Name);
ParseArray(name, DiffKind.Other, true, false);
ParseArray(name + "-new", DiffKind.NewRow, true, true);
ParseArray(name + "-deleted", DiffKind.DeletedRow, false, false);
}
/// <summary>
/// Set value of colName in target from source
/// </summary>
/// <returns>true if it was a real change; false if same value</returns>
private bool SetValue(TableDef tabledef, DiffRow source, string colName, Row target)
{
var coldef = tabledef.FindCol(colName);
if (coldef != null)
{
var oldValue = target.GetValue(coldef);
var newValue = source.Columns[colName];
bool isChange = (
(oldValue != null && !oldValue.Equals(newValue))
||
(!(oldValue == null && newValue == null))
);
if (isChange)
{
target.SetValue(coldef, newValue);
return(true);
}
}
return(false);
}
