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.

See Also:

Description of schema elements

Field Summary

Fields

Modifier and Type	Field and Description
Boolean	cache Whether to cache metadata (tables, functions and sub-schemas) generated by this schema.
List<JsonLattice>	lattices
List<JsonMaterialization>	materializations
String	name
List<Object>	path SQL-path.

Constructor Summary

Constructors

Constructor and Description
JsonSchema()

Method Summary

Methods

Modifier and Type	Method and 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 Detail

name

public String name

path

public List<Object> path

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

materializations

public final List<JsonMaterialization> materializations

lattices

public final List<JsonLattice> lattices

cache

public 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). However, it also leads to the problem of cache staleness. A particular schema implementation can override the Schema.contentsHaveChangedSince(long, long) method to tell Calcite when it should consider its cache to be out of date.

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.

Constructor Detail

JsonSchema

public JsonSchema()

Method Detail

accept

public abstract void accept(ModelHandler handler)

visitChildren

public void visitChildren(ModelHandler modelHandler)