org.apache.calcite.schema

Interface SchemaPlus

All Superinterfaces:

Schema

public interface SchemaPlus
extends Schema

Extension to the Schema interface.

Given a user-defined schema that implements the Schema interface, Calcite creates a wrapper that implements the SchemaPlus interface. This provides extra functionality, such as access to tables that have been added explicitly.

A user-defined schema does not need to implement this interface, but by the time a schema is passed to a method in a user-defined schema or user-defined table, it will have been wrapped in this interface.

SchemaPlus is intended to be used by users but not instantiated by them. Users should only use the SchemaPlus they are given by the system. The purpose of SchemaPlus is to expose to user code, in a read only manner, some of the extra information about schemas that Calcite builds up when a schema is registered. It appears in several SPI calls as context; for example SchemaFactory.create(SchemaPlus, String, java.util.Map) contains a parent schema that might be a wrapped instance of a user-defined Schema, or indeed might not.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.schema.Schema

Schema.TableType

Method Summary

Modifier and Type	Method and Description
void	add(String name, Function function) Adds a function to this schema.
void	add(String name, Lattice lattice) Adds a lattice to this schema.
void	add(String name, RelProtoDataType type) Adds a type to this schema.
SchemaPlus	add(String name, Schema schema) Adds a schema as a sub-schema of this schema, and returns the wrapped object.
void	add(String name, Table table) Adds a table to this schema.
String	getName() Returns the name of this schema.
@Nullable SchemaPlus	getParentSchema() Returns the parent schema, or null if this schema has no parent.
@Nullable SchemaPlus	getSubSchema(String name) Returns a sub-schema with a given name, or null.
boolean	isCacheEnabled()
boolean	isMutable() Returns whether the user is allowed to create new tables, functions and sub-schemas in this schema, in addition to those returned automatically by methods such as Schema.getTable(String).
default boolean	removeTable(String name) Removes a table from this schema, used e.g.
void	setCacheEnabled(boolean cache)
void	setPath(com.google.common.collect.ImmutableList<com.google.common.collect.ImmutableList<String>> path)
<T> T	unwrap(Class<T> clazz) Returns an underlying object.

Methods inherited from interface org.apache.calcite.schema.Schema

getExpression, getFunctionNames, getFunctions, getSubSchemaNames, getTable, getTableNames, getType, getTypeNames, snapshot

Method Detail

getParentSchema

@Nullable SchemaPlus getParentSchema()

Returns the parent schema, or null if this schema has no parent.

getName

String getName()

Returns the name of this schema.

The name must not be null, and must be unique within its parent. The root schema is typically named "".

getSubSchema

@Nullable SchemaPlus getSubSchema(String name)

Description copied from interface: Schema

Returns a sub-schema with a given name, or null.

Specified by:

getSubSchema in interface Schema

Parameters:

name - Sub-schema name

Returns:

Sub-schema with a given name, or null

add

SchemaPlus add(String name,
               Schema schema)

Adds a schema as a sub-schema of this schema, and returns the wrapped object.

add

void add(String name,
         Table table)

Adds a table to this schema.

removeTable

default boolean removeTable(String name)

Removes a table from this schema, used e.g. to clean-up temporary tables.

add

void add(String name,
         Function function)

Adds a function to this schema.

add

void add(String name,
         RelProtoDataType type)

Adds a type to this schema.

add

void add(String name,
         Lattice lattice)

Adds a lattice to this schema.

isMutable

boolean isMutable()

Description copied from interface: Schema

Returns whether the user is allowed to create new tables, functions and sub-schemas in this schema, in addition to those returned automatically by methods such as Schema.getTable(String).

Even if this method returns true, the maps are not modified. Calcite stores the defined objects in a wrapper object.

Specified by:

isMutable in interface Schema

Returns:

Whether the user is allowed to create new tables, functions and sub-schemas in this schema

unwrap

<T> T unwrap(Class<T> clazz)

Returns an underlying object.

setPath

void setPath(com.google.common.collect.ImmutableList<com.google.common.collect.ImmutableList<String>> path)

setCacheEnabled

void setCacheEnabled(boolean cache)

isCacheEnabled

boolean isCacheEnabled()