com.exasol.adapter.capabilities

Enum MainCapability

java.lang.Object

java.lang.Enum<MainCapability>

com.exasol.adapter.capabilities.MainCapability

All Implemented Interfaces:

Serializable, Comparable<MainCapability>

public enum MainCapability
extends Enum<MainCapability>

This is an enumeration of the main capabilities supported by the EXASOL Virtual Schema Framework.

Enum Constant Summary

Enum Constants

Enum Constant and Description
AGGREGATE_GROUP_BY_COLUMN Support aggregations with a group by clause consisting of columns.
AGGREGATE_GROUP_BY_EXPRESSION Support aggregations with a group by clause that contains expressions.
AGGREGATE_GROUP_BY_TUPLE Support aggregations with a group by clause with multiple group by columns or expressions.
AGGREGATE_HAVING Support aggregations with a having clause.
AGGREGATE_SINGLE_GROUP Support aggregations with a single group.
FILTER_EXPRESSIONS Support filter expressions.
JOIN Support for joins.
JOIN_CONDITION_ALL Support joins with any conditions.
JOIN_CONDITION_EQUI Support joins with equi-join conditions.
JOIN_TYPE_FULL_OUTER Support full outer joins.
JOIN_TYPE_INNER Support inner joins.
JOIN_TYPE_LEFT_OUTER Support left outer joins.
JOIN_TYPE_RIGHT_OUTER Support right outer joins.
LIMIT Support to limit the number of result rows.
LIMIT_WITH_OFFSET Support to limit the number of result rows including an offset.
ORDER_BY_COLUMN Support to order the result by columns.
ORDER_BY_EXPRESSION Support to order the result by expressions.
SELECTLIST_EXPRESSIONS Support expressions in the select list; Additional capabilities are required depending on the expression.
SELECTLIST_PROJECTION Support projections, i.e.

Method Summary

Modifier and Type	Method and Description
static MainCapability	valueOf(String name) Returns the enum constant of this type with the specified name.
static MainCapability[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

SELECTLIST_PROJECTION

public static final MainCapability SELECTLIST_PROJECTION

Support projections, i.e. request only a subset of all columns of the table.

Example: SELECT a FROM t;

SELECTLIST_EXPRESSIONS

public static final MainCapability SELECTLIST_EXPRESSIONS

Support expressions in the select list; Additional capabilities are required depending on the expression.

Example: SELECT a+1, ucase(b) FROM t;

FILTER_EXPRESSIONS

public static final MainCapability FILTER_EXPRESSIONS

Support filter expressions. Additional capabilities are required depending on the expression.

Example: SELECT * FROM t WHERE a>2

AGGREGATE_SINGLE_GROUP

public static final MainCapability AGGREGATE_SINGLE_GROUP

Support aggregations with a single group. This happens when an aggregation-function is used without a group by clause.

Example: SELECT min(a) FROM t;

AGGREGATE_GROUP_BY_COLUMN

public static final MainCapability AGGREGATE_GROUP_BY_COLUMN

Support aggregations with a group by clause consisting of columns.

Example: SELECT a, b, min(c) FROM t GROUP BY a, b;

AGGREGATE_GROUP_BY_EXPRESSION

public static final MainCapability AGGREGATE_GROUP_BY_EXPRESSION

Support aggregations with a group by clause that contains expressions.

Example: SELECT a+1, min(b) FROM t GROUP BY a+1;

AGGREGATE_GROUP_BY_TUPLE

public static final MainCapability AGGREGATE_GROUP_BY_TUPLE

Support aggregations with a group by clause with multiple group by columns or expressions. Note that you might additionally require AGGREGATE_GROUP_BY_EXPRESSION or AGGREGATE_GROUP_BY_COLUMN.

Example: SELECT a, b, min(c) FROM t GROUP BY a, b;

AGGREGATE_HAVING

public static final MainCapability AGGREGATE_HAVING

Support aggregations with a having clause. Additional capabilities might be required depending on the expression.

Example: SELECT a, min(b) FROM t GROUP BY a HAVING min(b)>10;

ORDER_BY_COLUMN

public static final MainCapability ORDER_BY_COLUMN

Support to order the result by columns.

Attention: This includes the capability to specify NULLS FIRST/LAST and ASC/DESC.

Example: SELECT a, b FROM t ORDER BY a, b DESC NULLS FIRST;

ORDER_BY_EXPRESSION

public static final MainCapability ORDER_BY_EXPRESSION

Support to order the result by expressions.

Attention: This includes the capability to specify NULLS FIRST/LAST and ASC/DESC

Example: SELECT a FROM t ORDER BY abs(a) ASC NULLS LAST;

LIMIT

public static final MainCapability LIMIT

Support to limit the number of result rows. Often used together with ordering.

Example: SELECT * FROM t 0

LIMIT_WITH_OFFSET

public static final MainCapability LIMIT_WITH_OFFSET

Support to limit the number of result rows including an offset.

Example: SELECT * FROM t LIMIT 100 OFFSET 10;

JOIN

public static final MainCapability JOIN

Support for joins. If you don't support this capability no joins will be generated in the push-down.

Attention: In order to generate joins in the push-down you additionally have to return at least one capability for join type and join condition.

JOIN_TYPE_INNER

public static final MainCapability JOIN_TYPE_INNER

Support inner joins. Example: SELECT * FROM t INNER JOIN u ON t.id = u.id

JOIN_TYPE_LEFT_OUTER

public static final MainCapability JOIN_TYPE_LEFT_OUTER

Support left outer joins. Example: SELECT * FROM t LEFT OUTER JOIN u ON t.id = u.id

JOIN_TYPE_RIGHT_OUTER

public static final MainCapability JOIN_TYPE_RIGHT_OUTER

Support right outer joins. Example: SELECT * FROM t RIGHT OUTER JOIN u ON t.id = u.id

JOIN_TYPE_FULL_OUTER

public static final MainCapability JOIN_TYPE_FULL_OUTER

Support full outer joins. Example: SELECT * FROM t FULL OUTER JOIN u ON t.id = u.id

JOIN_CONDITION_EQUI

public static final MainCapability JOIN_CONDITION_EQUI

Support joins with equi-join conditions. Example: SELECT * FROM t INNER JOIN u ON t.id = u.id SELECT * FROM t INNER JOIN u ON t.id = u.id + 3

JOIN_CONDITION_ALL

public static final MainCapability JOIN_CONDITION_ALL

Support joins with any conditions. Example: SELECT * FROM t INNER JOIN u ON t.x between(u.x, u.y)

Method Detail

values

public static MainCapability[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (MainCapability c : MainCapability.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static MainCapability valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null