/// <summary>
/// Appends a call to <c>JSON_EXTRACT</c> from the current column and JSON path, e.g. <c>JSON_EXTRACT(T0."MyJson", '$.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 Json(this IProjectionAttribute attribute)
{
IJsonMetadata json = attribute.Metadata.Identity.Require <IJsonMetadata>();
IProjectionMetadata valueMetadata = attribute.Metadata;
IProjectionMetadata rootMetadata = json.MemberOf.Identity.Lookup <IProjectionMetadata>();
attribute = attribute.Append("JSON_EXTRACT(");
attribute = attribute.With(metadata: rootMetadata).Col();
attribute = attribute.Append(",");
attribute = attribute.With(metadata: valueMetadata).JsonPath();
attribute = attribute.Append(")");
return(attribute);
}
public static IProjection IsEq(this IProjection projection, IProjection other)
{
List <IProjectionAttribute> newAttrs = new List <IProjectionAttribute>();
foreach (var(l, r) in projection.Attrs().Zip(other.Attrs()))
{
IProjectionAttribute newAttr = l;
newAttr = newAttr.Eq();
newAttr = newAttr.With(metadata: r.Metadata, field: r.Field).Par();
newAttr = newAttr.With(metadata: l.Metadata, field: l.Field);
newAttrs.Add(newAttr);
}
ProjectionOptions newOptions = new ProjectionOptions(projection.Options)
{
Separator = Environment.NewLine + "AND" + Environment.NewLine,
};
return(projection.With(attributes: newAttrs, options: newOptions));
}
public static IProjection IsEq(this IProjection projection, IProjection other)
{
List <IProjectionAttribute> newHeader = new List <IProjectionAttribute>();
foreach (var(l, r) in projection.Attrs().Zip(other.Attrs()))
{
IProjectionAttribute newAttr = l;
newAttr = newAttr.Eq();
newAttr = newAttr.With(data: r.Data).Par();
newAttr = newAttr.With(data: l.Data);
newHeader.Add(newAttr);
}
ProjectionOptions newOptions = new ProjectionOptions(projection.Options)
{
Separator = Environment.NewLine + "AND" + Environment.NewLine,
};
return(projection.With(header: newHeader, options: newOptions));
}
public static IProjectionAttribute ValList(this IProjection projection, Func <IProjectionAttribute, IProjectionAttribute> itemFactory)
{
if (projection.Source == null)
{
throw ProjectionException.ValueNotFound(projection);
}
IField[] items = new Relation(projection.Source, projection.Metadata.Identity.Name).Column().ToArray();
IProjectionAttribute attribute = projection.Attr();
if (items.Length == 0)
{
return(attribute);
}
attribute = itemFactory(attribute.With(metadata: attribute.Metadata, field: () => items[0]));
foreach (IField item in items.Skip(1))
{
attribute = itemFactory(attribute.With(field: () => item).Append(", "));
}
return(attribute);
}
