public class InformixDialect extends JdbcDialectImpl
Dialect for the Informix database.Dialect.DatabaseProduct, Dialect.Datatype| Modifier and Type | Field and Description |
|---|---|
static JdbcDialectFactory |
FACTORY |
databaseProduct, permitsSelectNotInGroupBy, productVersion| Constructor and Description |
|---|
InformixDialect(Connection connection)
Creates an InformixDialect.
|
| Modifier and Type | Method and Description |
|---|---|
boolean |
allowsFromQuery()
Returns whether this Dialect allows a subquery in the from clause,
for example
SELECT * FROM (SELECT * FROM t) AS
x |
String |
generateOrderByNulls(String expr,
boolean ascending,
boolean collateNullsLast)
Generates SQL to force null values to collate last.
|
boolean |
supportsGroupByExpressions()
Returns whether this Dialect supports expressions in the GROUP BY
clause.
|
allowsAs, allowsCompoundCountDistinct, allowsCountDistinct, allowsCountDistinctWithOtherAggs, allowsDdl, allowsDialectSharing, allowsJoinOn, allowsMultipleCountDistinct, allowsMultipleDistinctSqlMeasures, allowsOrderByAlias, allowsRegularExpressionInWhereClause, allowsSelectNotInGroupBy, appendHintsAfterFromClause, caseWhenElse, computeStatisticsProviders, deduceIdentifierQuoteString, deduceMaxColumnNameLength, deduceProductName, deduceProductVersion, deduceReadOnly, deduceSupportedResultSetStyles, deduceSupportsSelectNotInGroupBy, generateCountExpression, generateInline, generateInlineForAnsi, generateInlineGeneric, generateOrderByNullsAnsi, generateOrderItem, generateRegularExpression, getDatabaseProduct, getMaxColumnNameLength, getProduct, getQuoteIdentifierString, getStatisticsProviders, getType, isDatabase, needsExponent, quote, quoteBooleanLiteral, quoteDateLiteral, quoteDateLiteral, quoteIdentifier, quoteIdentifier, quoteIdentifier, quoteIdentifier, quoteNumericLiteral, quoteStringLiteral, quoteTimeLiteral, quoteTimestampLiteral, requiresAliasForFromQuery, requiresGroupByAlias, requiresHavingAlias, requiresOrderByAlias, requiresUnionOrderByExprToBeInSelectClause, requiresUnionOrderByOrdinal, supportsGroupingSets, supportsMultiValueInExpr, supportsResultSetConcurrency, supportsUnlimitedValueList, toString, toUpperpublic static final JdbcDialectFactory FACTORY
public InformixDialect(Connection connection) throws SQLException
connection - ConnectionSQLExceptionpublic boolean allowsFromQuery()
DialectSELECT * FROM (SELECT * FROM t) AS
xallowsFromQuery in interface DialectallowsFromQuery in class JdbcDialectImplDialect.requiresAliasForFromQuery()public String generateOrderByNulls(String expr, boolean ascending, boolean collateNullsLast)
JdbcDialectImplThis default implementation makes use of the ANSI SQL 1999 CASE-WHEN-THEN-ELSE in conjunction with IS NULL syntax. The resulting SQL will look something like this:
CASE WHEN "expr" IS NULL THEN 0 ELSE 1 END
You can override this method for a particular database to use something more efficient, like ISNULL().
ANSI SQL provides the syntax "ASC/DESC NULLS LAST" and
"ASC/DESC NULLS FIRST". If your database supports the ANSI
syntax, implement this method by calling
JdbcDialectImpl.generateOrderByNullsAnsi(java.lang.String, boolean, boolean).
This method is only called from
JdbcDialectImpl.generateOrderItem(String, boolean, boolean, boolean).
Some dialects override that method and therefore never call
this method.
generateOrderByNulls in class JdbcDialectImplexpr - Expression.ascending - Whether ascending.collateNullsLast - Whether nulls should appear first or last.public boolean supportsGroupByExpressions()
DialectsupportsGroupByExpressions in interface DialectsupportsGroupByExpressions in class JdbcDialectImplCopyright © 2017 Hitachi Vantara. All rights reserved.