private void BuildValuesAsSelectsUnion(IList <SqlField> sourceFields, SqlValuesTable source, IReadOnlyList <ISqlExpression[]> rows)
{
var columnTypes = new SqlDataType[sourceFields.Count];
for (var i = 0; i < sourceFields.Count; i++)
{
columnTypes[i] = new SqlDataType(sourceFields[i]);
}
StringBuilder
.AppendLine();
AppendIndent();
for (var i = 0; i < rows.Count; i++)
{
if (i > 0)
{
StringBuilder
.AppendLine();
AppendIndent();
StringBuilder.AppendLine("\tUNION ALL");
AppendIndent();
}
// build record select
StringBuilder.Append("\tSELECT ");
var row = rows[i];
for (var j = 0; j < row.Length; j++)
{
var value = row[j];
if (j > 0)
{
StringBuilder.Append(InlineComma);
}
if (IsSqlValuesTableValueTypeRequired(source, rows, i, j))
{
BuildTypedExpression(columnTypes[j], value);
}
else
{
BuildExpression(value);
}
// add aliases only for first row
if (RequiresConstantColumnAliases || i == 0)
{
StringBuilder.Append(" AS ");
Convert(StringBuilder, sourceFields[j].PhysicalName, ConvertType.NameToQueryField);
}
}
if (FakeTable != null)
{
StringBuilder.Append(" FROM ");
BuildFakeTableName();
}
}
}
protected override bool MergeSourceValueTypeRequired(SqlValuesTable sourceEnumerable, int row, int column)
{
/* DB2 doesn't like NULLs without type information
* : ERROR [42610] [IBM][DB2/NT64] SQL0418N The statement was not processed because the statement
* contains an invalid use of one of the following: an untyped parameter marker, the DEFAULT keyword
* , or a null value.
*
* See https://stackoverflow.com/questions/13381898
*
* Unfortunatelly, just use typed parameter doesn't help
*
* To fix it we need to cast at least one NULL in column if all column values are null.
* We will do it for last row, when we know that there is no non-null values in column and type hint
* needed.
*
* One thing I don't like is that in some cases DB2 can process query without type hints
*/
if (row == -1)
{
return(true);
}
if (row != 0)
{
return(false);
}
// check if column contains NULL in all rows
return(sourceEnumerable.Rows.All(r => r[column] is SqlValue value && value.Value == null));
}
protected override bool MergeSourceValueTypeRequired(SqlValuesTable source, IReadOnlyList <ISqlExpression[]> rows, int row, int column)
{
if (row == -1)
{
return(true);
}
var expr = rows[row][column];
if (!MergeSourceValueTypeRequired(expr))
{
return(false);
}
//Base DB2 impl follows
// empty source (single row with all values == NULL)
if (row == -1)
{
return(true);
}
// we add type hints to first row only
if (row != 0)
{
return(false);
}
// add type hint only if column contains NULL in all rows
return(rows.All(r => r[column] is SqlValue value && (value.Value == null ||
(value is INullable nullable && nullable.IsNull))));
}
public EnumerableContext(ExpressionBuilder builder, BuildInfo buildInfo, SelectQuery query, Type elementType,
Expression source)
{
Parent = buildInfo.Parent;
Builder = builder;
Expression = buildInfo.Expression;
SelectQuery = query;
_elementType = elementType;
_entityDescriptor = Builder.MappingSchema.GetEntityDescriptor(elementType);
Table = new SqlValuesTable(source);
}
public EnumerableContext(ExpressionBuilder builder, BuildInfo buildInfo, SelectQuery query, Type elementType)
{
Parent = buildInfo.Parent;
Builder = builder;
Expression = buildInfo.Expression;
SelectQuery = query;
_elementType = elementType;
_entityDescriptor = Builder.MappingSchema.GetEntityDescriptor(elementType);
Table = BuildValuesTable();
foreach (var field in Table.Fields)
{
SelectQuery.Select.AddNew(field);
}
SelectQuery.From.Table(Table);
}
protected override bool MergeSourceValueTypeRequired(SqlValuesTable source, IReadOnlyList <ISqlExpression[]> rows, int row, int column)
{
if (row == 0)
{
// without type Firebird with convert string values in column to CHAR(LENGTH_OF_BIGGEST_VALUE_IN_COLUMN) with
// padding shorter values with spaces
if (rows.Any(r => r[column] is SqlValue value && value.Value is string))
{
_typedColumns.Add(Tuple.Create(source, column));
return(rows[0][column] is SqlValue val && val.Value != null);
}
return(false);
}
return(_typedColumns.Contains(Tuple.Create(source, column)) &&
rows[row][column] is SqlValue sqlValue && sqlValue.Value != null);
}
protected override bool MergeSourceValueTypeRequired(SqlValuesTable source, IReadOnlyList<ISqlExpression[]> rows, int row, int column) {
if (row == -1) {
return true;
}
var expr = rows[row][column];
if (MergeSourceValueTypeRequired(expr)) {
return true;
}
switch (row) {
case -1:
return true;
default:
return false;
case 0:
return rows.All(delegate (ISqlExpression[] r) {
var sqlValue = r[column] as SqlValue;
return sqlValue != null && (sqlValue.Value == null || ((sqlValue as INullable)?.IsNull ?? false));
});
}
}
// Informix is too lazy to infer types itself from context protected override bool MergeSourceValueTypeRequired(SqlValuesTable sourceEnumerable, int row, int column) => true;
// Informix is too lazy to infer types itself from context protected override bool IsSqlValuesTableValueTypeRequired(SqlValuesTable source, IReadOnlyList <ISqlExpression[]> rows, int row, int column) => true;
/// <summary> /// Checks that value in specific row and column in enumerable source requires type information generation. /// </summary> /// <param name="source">Merge source table.</param> /// <param name="rows">Merge source data.</param> /// <param name="row">Index of data row to check. Could contain -1 to indicate that this is a check for empty source NULL value.</param> /// <param name="column">Index of data column to check in row.</param> /// <returns>Returns <c>true</c>, if generated SQL should include type information for value at specified position, otherwise <c>false</c> returned.</returns> protected virtual bool IsSqlValuesTableValueTypeRequired(SqlValuesTable source, IReadOnlyList <ISqlExpression[]> rows, int row, int column) => false;
