/// <summary>
/// Appends the current column name in unqualified form, e.g. <c>"MyColumn"</c>, to the attribute buffer.
/// </summary>
/// <param name="attribute">The current attribute.</param>
/// <returns>A new attribute containing the appended buffer.</returns>
public static IProjectionAttribute ColName(this IProjectionAttribute attribute)
{
ITableMetadata column = ProjectionHelper.GetPreferredColumnMetadata(attribute);
string identifier = attribute.Context.Domain.Dialect.Identifier(column.ColumnName);
return(attribute.Append(identifier));
}
/// <summary>
/// Appends the current table alias, e.g. <c>T0</c>, to the attribute buffer.
/// </summary>
/// <param name="attribute">The current attribute.</param>
/// <returns>A new attribute containing the appended buffer.</returns>
public static IProjectionAttribute Ali(this IProjectionAttribute attribute)
{
ITableMetadata table = ProjectionHelper.GetTableMetadata(attribute);
string alias = attribute.Context.Lookup.Table(attribute.Identity, table.Identity);
return(attribute.Append(alias));
}
/// <summary>
/// Appends the current JSON path literal, e.g. <c>'$.my.value'</c>, to the attribute buffer.
/// </summary>
/// <param name="attribute">The current attribute.</param>
/// <returns>A new attribute containing the appended buffer.</returns>
public static IProjectionAttribute JsonPath(this IProjectionAttribute attribute)
{
IJsonMetadata metadata = ProjectionHelper.GetJsonMetadata(attribute.Metadata);
string literal = attribute.Context.Domain.Dialect.String(metadata.Path);
return(attribute.Append(literal));
}
/// <summary>
/// Appends the current table name, e.g. <c>"MyTable"</c>, to the attribute buffer.
/// </summary>
/// <param name="attribute">The current attribute.</param>
/// <returns>A new attribute containing the appended buffer.</returns>
public static IProjectionAttribute TblName(this IProjectionAttribute attribute)
{
ITableMetadata table = ProjectionHelper.GetTableMetadata(attribute);
string qualifier = attribute.Context.Domain.Dialect.Qualifier;
string tableName = string.Join(qualifier, table.TableName.Select(attribute.Context.Domain.Dialect.Identifier));
return(attribute.Append(tableName));
}
/// <summary>
/// Appends the current variable name, e.g. <c>@V0</c>, to the attribute buffer.
/// </summary>
/// <param name="attribute">The current attribute.</param>
/// <returns>A new attribute containing the appended buffer.</returns>
public static IProjectionAttribute Var(this IProjectionAttribute attribute)
{
IField field = ProjectionHelper.GetFieldValue(attribute);
string variableName = attribute.Context.Lookup.Variable(attribute.Identity, field);
string dialectName = attribute.Context.Domain.Dialect.Variable(variableName);
return(attribute.Append(dialectName));
}
/// <summary>
/// Appends mappings between the current qualified columns and their properties, e.g. <c>T0."MyColumn" AS "Item.MyValue"</c>, to the projection buffer. Identical to calling <c>Cols().As().Props()</c>.
/// </summary>
/// <param name="projection">The current projection</param>
/// <param name="tblAlias">The table alias to qualify each column name with.</param>
/// <returns>A new projection containing the appended buffer.</returns>
public static IProjection Star(this IProjection projection, string tblAlias = null)
{
if (!projection.Any())
{
throw ProjectionException.AttributesNotFound(projection.Metadata);
}
IProjectionMetadata metadata = ProjectionHelper.GetPreferredTableMetadata(projection.Metadata);
return(projection.With(metadata).Cols(tblAlias).As().Props());
}
/// <summary>
/// Appends mappings between the current qualified columns and their properties, e.g. <c>T0."MyColumn" AS "Item.MyValue"</c>, to the projection buffer. Identical to calling <c>Cols().As().Props()</c>.
/// </summary>
/// <param name="projection">The current projection</param>
/// <returns>A new projection containing the appended buffer.</returns>
public static IProjection Star(this IProjection projection)
{
if (!projection.Any())
{
throw ProjectionException.FromProjection(projection, "No attributes found.");
}
IProjectionMetadata metadata = ProjectionHelper.GetPreferredTableMetadata(projection).Identity.GetMetadata <IProjectionMetadata>();
return(projection.With(metadata).Cols().As().Props());
}
/// <summary>
/// Appends the current value in safe literal form, e.g. <c>1</c>, to the attribute buffer. Parameters are used for unsafe literals.
/// </summary>
/// <param name="attribute">The current attribute.</param>
/// <returns>A new attribute containing the appended buffer.</returns>
public static IProjectionAttribute Lit(this IProjectionAttribute attribute)
{
IField field = ProjectionHelper.GetFieldValue(attribute);
string literal = attribute.Context.Domain.Dialect.Literal(field?.Value);
if (literal == null)
{
return(attribute.Par());
}
else
{
return(attribute.Append(literal));
}
}
/// <summary>
/// Navigates the current projection to a selected target.
/// </summary>
/// <param name="projection">The current projection.</param>
/// <param name="expression">Expression selecting a projection target.</param>
/// <returns>A new projection from the selected target.</returns>
public static IProjection <TProperty> For <TModel, TProperty>(this IProjection <TModel> projection, Expression <Func <TModel, TProperty> > expression)
{
IProjectionMetadata metadata = ProjectionHelper.GetMetadataFromRelativeLambda(projection, expression);
return(projection.With(metadata).Cast <TProperty>());
}
