Package org.apache.calcite.model

Class JsonSchema

java.lang.Object

org.apache.calcite.model.JsonSchema

Direct Known Subclasses:

JsonJdbcSchema, JsonMapSchema

public abstract class JsonSchema
extends Object

Schema schema element.

Occurs within JsonRoot.schemas.

See Also:

• Description of schema elements

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	JsonSchema.Type	Built-in schema types.

Field Summary

Fields

Modifier and Type	Field	Description
final @Nullable Boolean	autoLattice	Whether to create lattices in this schema based on queries occurring in other schemas.
final @Nullable Boolean	cache	Whether to cache metadata (tables, functions and sub-schemas) generated by this schema.
final List<JsonLattice>	lattices
final List<JsonMaterialization>	materializations	List of tables in this schema that are materializations of queries.
final String	name	Name of the schema.
final @Nullable List<Object>	path	SQL path that is used to resolve functions used in this schema.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JsonSchema(String name, @Nullable List<Object> path, @Nullable Boolean cache, @Nullable Boolean autoLattice)

Method Summary

Modifier and Type	Method	Description
abstract void	accept(ModelHandler handler)
void	visitChildren(ModelHandler modelHandler)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

name

public final String name

Name of the schema.

Required.

See Also:

• JsonRoot.defaultSchema

path

public final @Nullable List<Object> path

SQL path that is used to resolve functions used in this schema.

May be null, or a list, each element of which is a string or a string-list.

For example,

path: [ ['usr', 'lib'], 'lib' ]

declares a path with two elements: the schema '/usr/lib' and the schema '/lib'. Most schemas are at the top level, and for these you can use a string.

materializations

public final List<JsonMaterialization> materializations

List of tables in this schema that are materializations of queries.

The list may be empty.

lattices

public final List<JsonLattice> lattices

cache

public final @Nullable Boolean cache

Whether to cache metadata (tables, functions and sub-schemas) generated by this schema. Default value is true.

If false, Calcite will go back to the schema each time it needs metadata, for example, each time it needs a list of tables in order to validate a query against the schema.

If true, Calcite will cache the metadata the first time it reads it. This can lead to better performance, especially if name-matching is case-insensitive (see Lex.caseSensitive).

Tables, functions and sub-schemas explicitly created in a schema are not affected by this caching mechanism. They always appear in the schema immediately, and are never flushed.

autoLattice

public final @Nullable Boolean autoLattice

Whether to create lattices in this schema based on queries occurring in other schemas. Default value is false.

Constructor Details

JsonSchema

protected JsonSchema(String name,
 @Nullable List<Object> path,
 @Nullable Boolean cache,
 @Nullable Boolean autoLattice)

Method Details

accept

public abstract void accept(ModelHandler handler)

visitChildren

public void visitChildren(ModelHandler modelHandler)