public Class H2Dialect

Overrides org.hibernate.dialect.Dialect.bindLimitParametersFirst.

Doc from org.hibernate.dialect.Dialect.bindLimitParametersFirst.

Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?

Returns:boolean

true if limit parameters should come before other parameters

Overrides org.hibernate.dialect.Dialect.bindLimitParametersInReverseOrder.

Doc from org.hibernate.dialect.Dialect.bindLimitParametersInReverseOrder.

ANSI SQL defines the LIMIT clause to be in the form LIMIT offset, limit. Does this dialect require us to bind the parameters in reverse order?

Returns:boolean

true if the correct order is limit, offset

Overrides org.hibernate.dialect.Dialect.doesReadCommittedCauseWritersToBlockReaders.

Doc from org.hibernate.dialect.Dialect.doesReadCommittedCauseWritersToBlockReaders.

For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released?

Returns:boolean

True if writers block readers to achieve READ_COMMITTED; false otherwise.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.dropTemporaryTableAfterUse.

Doc from org.hibernate.dialect.Dialect.dropTemporaryTableAfterUse.

Do we need to drop the temporary table after use?

Returns:boolean

True if the table should be dropped.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.getAddColumnString.

Doc from org.hibernate.dialect.Dialect.getAddColumnString.

The syntax used to add a column to a table (optional).

Returns:String

The "add column" fragment.

Overrides org.hibernate.dialect.Dialect.getCreateSequenceString.

Doc from org.hibernate.dialect.Dialect.getCreateSequenceString.

Typically dialects which support sequences can create a sequence with a single command. This is convenience form of getCreateSequenceStrings to help facilitate that.

Dialects which support sequences and can create a sequence in a single command need *only* override this method. Dialects which support sequences but require multiple commands to create a sequence should instead override getCreateSequenceStrings.

Parameters

sequenceName:String

The name of the sequence

Returns:String

The sequence creation command

Overrides org.hibernate.dialect.Dialect.getCreateTemporaryTableString.

Doc from org.hibernate.dialect.Dialect.getCreateTemporaryTableString.

Command used to create a temporary table.

Returns:String

The command used to create a temporary table.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.getCurrentTimestampSelectString.

Doc from org.hibernate.dialect.Dialect.getCurrentTimestampSelectString.

Retrieve the command used to retrieve the current timestamp from the database.

Returns:String

The command.

Overrides org.hibernate.dialect.Dialect.getDropSequenceString.

Doc from org.hibernate.dialect.Dialect.getDropSequenceString.

Typically dialects which support sequences can drop a sequence with a single command. This is convenience form of getDropSequenceStrings to help facilitate that.

Dialects which support sequences and can drop a sequence in a single command need *only* override this method. Dialects which support sequences but require multiple commands to drop a sequence should instead override getDropSequenceStrings.

Parameters

sequenceName:String

The name of the sequence

Returns:String

The sequence drop commands

Overrides org.hibernate.dialect.Dialect.getForUpdateString.

Doc from org.hibernate.dialect.Dialect.getForUpdateString.

Get the string to append to SELECT statements to acquire locks for this dialect.

Returns:String

The appropriate FOR UPDATE clause string.

Overrides org.hibernate.dialect.Dialect.getIdentityColumnString.

Doc from org.hibernate.dialect.Dialect.getIdentityColumnString.

The syntax used during DDL to define a column as being an IDENTITY.

Returns:String

The appropriate DDL fragment.

Overrides org.hibernate.dialect.Dialect.getIdentityInsertString.

Doc from org.hibernate.dialect.Dialect.getIdentityInsertString.

The keyword used to insert a generated value into an identity column (or null). Need if the dialect does not support inserts that specify no column values.

Returns:String

The appropriate keyword.

Overrides org.hibernate.dialect.Dialect.getIdentitySelectString.

Doc from org.hibernate.dialect.Dialect.getIdentitySelectString.

Get the select command to use to retrieve the last generated IDENTITY value.

Returns:String

The appropriate select command

Overrides org.hibernate.dialect.Dialect.getLimitString.

Doc from org.hibernate.dialect.Dialect.getLimitString.

Apply s limit clause to the query.

Typically dialects utilize variable limit clauses when they support limits. Thus, when building the select command we do not actually need to know the limit or the offest since we will just be using placeholders.

Here we do still pass along whether or not an offset was specified so that dialects not supporting offsets can generate proper exceptions. In general, dialects will override one or the other of this method and getLimitString(String, int, int).

Parameters

sql:String

The query to which to apply the limit.

hasOffset:boolean

Is the query requesting an offset?

Returns:String

the modified SQL

Overrides org.hibernate.dialect.Dialect.getQuerySequencesString.

Doc from org.hibernate.dialect.Dialect.getQuerySequencesString.

Get the select command used retrieve the names of all sequences.

Returns:String

The select command; or null if sequences are not supported.

Overrides org.hibernate.dialect.Dialect.getSelectSequenceNextValString.

Doc from org.hibernate.dialect.Dialect.getSelectSequenceNextValString.

Generate the select expression fragment that will retrieve the next value of a sequence as part of another (typically DML) statement.

This differs from getSequenceNextValString(String) in that this should return an expression usable within another statement.

Parameters

sequenceName:String

the name of the sequence

Returns:String

The "nextval" fragment.

Overrides org.hibernate.dialect.Dialect.getSequenceNextValString.

Doc from org.hibernate.dialect.Dialect.getSequenceNextValString.

Generate the appropriate select statement to to retrieve the next value of a sequence.

This should be a "stand alone" select statement.

Parameters

sequenceName:String

the name of the sequence

Returns:String

String The "nextval" select string.

Overrides org.hibernate.dialect.Dialect.getViolatedConstraintNameExtracter.

Overrides org.hibernate.dialect.Dialect.isCurrentTimestampSelectStringCallable.

Doc from org.hibernate.dialect.Dialect.isCurrentTimestampSelectStringCallable.

Should the value returned by getCurrentTimestampSelectString be treated as callable. Typically this indicates that JDBC escape syntax is being used...

Returns:boolean

True if the getCurrentTimestampSelectString return is callable; false otherwise.

Overrides org.hibernate.dialect.Dialect.performTemporaryTableDDLInIsolation.

Doc from org.hibernate.dialect.Dialect.performTemporaryTableDDLInIsolation.

Does the dialect require that temporary table DDL statements occur in isolation from other statements? This would be the case if the creation would cause any current transaction to get committed implicitly.

JDBC defines a standard way to query for this information via the java.sql.DatabaseMetaData#dataDefinitionCausesTransactionCommit() method. However, that does not distinguish between temporary table DDL and other forms of DDL; MySQL, for example, reports DDL causing a transaction commit via its driver, even though that is not the case for temporary table DDL.

Possible return values and their meanings:

• Boolean#TRUE - Unequivocally, perform the temporary table DDL in isolation.
• Boolean#FALSE - Unequivocally, do not perform the temporary table DDL in isolation.
• null - defer to the JDBC driver response in regards to java.sql.DatabaseMetaData#dataDefinitionCausesTransactionCommit()

Returns:Boolean

see the result matrix above.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.supportsCurrentTimestampSelection.

Doc from org.hibernate.dialect.Dialect.supportsCurrentTimestampSelection.

Does this dialect support a way to retrieve the database's current timestamp value?

Returns:boolean

True if the current timestamp can be retrieved; false otherwise.

Overrides org.hibernate.dialect.Dialect.supportsIdentityColumns.

Doc from org.hibernate.dialect.Dialect.supportsIdentityColumns.

Does this dialect support identity column key generation?

Returns:boolean

True if IDENTITY columns are supported; false otherwise.

Overrides org.hibernate.dialect.Dialect.supportsIfExistsAfterTableName.

Overrides org.hibernate.dialect.Dialect.supportsLimit.

Doc from org.hibernate.dialect.Dialect.supportsLimit.

Does this dialect support some form of limiting query results via a SQL clause?

Returns:boolean

True if this dialect supports some form of LIMIT.

Overrides org.hibernate.dialect.Dialect.supportsLobValueChangePropogation.

Doc from org.hibernate.dialect.Dialect.supportsLobValueChangePropogation.

Does the dialect support propagating changes to LOB values back to the database? Talking about mutating the internal value of the locator as opposed to supplying a new locator instance...

For BLOBs, the internal value might be changed by: java.sql.Blob#setBinaryStream, java.sql.Blob#setBytes(long, byte[]), java.sql.Blob#setBytes(long, byte[], int, int), or java.sql.Blob#truncate(long).

For CLOBs, the internal value might be changed by: java.sql.Clob#setAsciiStream(long), java.sql.Clob#setCharacterStream(long), java.sql.Clob#setString(long, String), java.sql.Clob#setString(long, String, int, int), or java.sql.Clob#truncate(long).

NOTE : I do not know the correct answer currently for databases which (1) are not part of the cruise control process or (2) do not supportsExpectedLobUsagePattern.

Returns:boolean

True if the changes are propagated back to the database; false otherwise.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.supportsPooledSequences.

Doc from org.hibernate.dialect.Dialect.supportsPooledSequences.

Does this dialect support "pooled" sequences. Not aware of a better name for this. Essentially can we specify the initial and increment values?

Returns:boolean

True if such "pooled" sequences are supported; false otherwise.

Overrides org.hibernate.dialect.Dialect.supportsSequences.

Doc from org.hibernate.dialect.Dialect.supportsSequences.

Does this dialect support sequences?

Returns:boolean

True if sequences supported; false otherwise.

Overrides org.hibernate.dialect.Dialect.supportsTemporaryTables.

Doc from org.hibernate.dialect.Dialect.supportsTemporaryTables.

Does this dialect support temporary tables?

Returns:boolean

True if temp tables are supported; false otherwise.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.supportsTupleDistinctCounts.

Doc from org.hibernate.dialect.Dialect.supportsTupleDistinctCounts.

Does this dialect support `count(distinct a,b)`?

Returns:boolean

True if the database supports counting disintct tuples; false otherwise.

Annotations

@Override

Overrides org.hibernate.dialect.Dialect.supportsUnionAll.

Doc from org.hibernate.dialect.Dialect.supportsUnionAll.

Does this dialect support UNION ALL, which is generally a faster variant of UNION?

Returns:boolean

True if UNION ALL is supported; false otherwise.

Overrides org.hibernate.dialect.Dialect.supportsUnique.

Doc from org.hibernate.dialect.Dialect.supportsUnique.

Does this dialect support the UNIQUE column syntax?

Returns:boolean

boolean