本文整理汇总了C#中Deveel.Data.Sql.Expressions.SqlExpression.IsConstant方法的典型用法代码示例。如果您正苦于以下问题：C# SqlExpression.IsConstant方法的具体用法？C# SqlExpression.IsConstant怎么用？C# SqlExpression.IsConstant使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类Deveel.Data.Sql.Expressions.SqlExpression的用法示例。
在下文中一共展示了SqlExpression.IsConstant方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C#代码示例。
示例1: SimpleSelect
public static ITable SimpleSelect(this ITable table, IQueryContext context, ObjectName columnName, SqlExpressionType op, SqlExpression exp)
{
// Find the row with the name given in the condition.
int column = table.FindColumn(columnName);
if (column == -1)
throw new ArgumentException(String.Format("Unable to find the column {0} in the condition.", columnName.Name));
// If we are doing a sub-query search
if (op.IsSubQuery()) {
// We can only handle constant expressions in the RHS expression, and
// we must assume that the RHS is a Expression[] array.
if (exp.ExpressionType != SqlExpressionType.Constant &&
exp.ExpressionType != SqlExpressionType.Tuple)
throw new ArgumentException();
IEnumerable<SqlExpression> list;
if (exp.ExpressionType == SqlExpressionType.Constant) {
var tob = ((SqlConstantExpression) exp).Value;
if (tob.Type is ArrayType) {
var array = (SqlArray) tob.Value;
list = array;
} else {
throw new Exception("Error with format or RHS expression.");
}
} else {
list = ((SqlTupleExpression) exp).Expressions;
}
// Construct a temporary table with a single column that we are
// comparing to.
var col = table.TableInfo[column];
var ttable = TemporaryTable.SingleColumnTable(table.DatabaseContext, col.ColumnName, col.ColumnType);
foreach (var expression in list) {
var rowNum = ttable.NewRow();
var evalExp = (SqlConstantExpression)expression.Evaluate(context, null, null);
ttable.SetValue(rowNum, 0, evalExp.Value);
}
ttable.BuildIndexes();
// Perform the any/all sub-query on the constant table.
return table.SelectAnyAllNonCorrelated(new[] { columnName }, op, ttable);
}
{
if (!exp.IsConstant())
throw new ArgumentException("The search expression is not constant.");
var evalExp = exp.Evaluate(context, null);
if (evalExp.ExpressionType != SqlExpressionType.Constant)
throw new InvalidOperationException();
var value = ((SqlConstantExpression) evalExp).Value;
IEnumerable<int> rows;
if (op == SqlExpressionType.Like ||
op == SqlExpressionType.NotLike
/* TODO: ||
op.IsOfType(BinaryOperatorType.Regex)*/) {
/*
TODO:
if (op.IsOfType(BinaryOperatorType.Regex)) {
rows = SelectFromRegex(column, op, value);
} else {
*/
rows = table.SelectFromPattern(column, op, value);
} else {
// Is the column we are searching on indexable?
var colInfo = table.TableInfo[column];
if (!colInfo.IsIndexable)
throw new InvalidOperationException(String.Format("Column {0} os type {1} cannot be searched.", colInfo.ColumnName,
colInfo.ColumnType));
rows = table.SelectRows(column, op, value);
}
return new VirtualTable(table, rows.ToArray()) {SortColumn = column};
}
}