Package org.hibernate.dialect

Class H2Dialect

java.lang.Object
org.hibernate.dialect.Dialect
org.hibernate.dialect.H2Dialect
public class H2Dialect extends Dialect
A dialect compatible with the H2 database.

  • Constructor Details

    • H2Dialect

      public H2Dialect()

  • Method Details

    • getAddColumnString

      public String getAddColumnString()
      Description copied from class: Dialect
      The syntax used to add a column to a table (optional).
      Overrides:
      getAddColumnString in class Dialect
      Returns:
      The "add column" fragment.

    • supportsIdentityColumns

      public boolean supportsIdentityColumns()
      Description copied from class: Dialect
      Does this dialect support identity column key generation?
      Overrides:
      supportsIdentityColumns in class Dialect
      Returns:
      True if IDENTITY columns are supported; false otherwise.

    • getIdentityColumnString

      public String getIdentityColumnString()
      Description copied from class: Dialect
      The syntax used during DDL to define a column as being an IDENTITY.
      Overrides:
      getIdentityColumnString in class Dialect
      Returns:
      The appropriate DDL fragment.

    • getIdentitySelectString

      public String getIdentitySelectString()
      Description copied from class: Dialect
      Get the select command to use to retrieve the last generated IDENTITY value.
      Overrides:
      getIdentitySelectString in class Dialect
      Returns:
      The appropriate select command

    • getIdentityInsertString

      public String getIdentityInsertString()
      Description copied from class: Dialect
      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.
      Overrides:
      getIdentityInsertString in class Dialect
      Returns:
      The appropriate keyword.

    • getForUpdateString

      public String getForUpdateString()
      Description copied from class: Dialect
      Get the string to append to SELECT statements to acquire locks for this dialect.
      Overrides:
      getForUpdateString in class Dialect
      Returns:
      The appropriate FOR UPDATE clause string.

    • supportsUnique

      public boolean supportsUnique()
      Description copied from class: Dialect
      Does this dialect support the UNIQUE column syntax?
      Overrides:
      supportsUnique in class Dialect
      Returns:
      boolean

    • supportsLimit

      public boolean supportsLimit()
      Description copied from class: Dialect
      Does this dialect support some form of limiting query results via a SQL clause?
      Overrides:
      supportsLimit in class Dialect
      Returns:
      True if this dialect supports some form of LIMIT.

    • getLimitString

      public String getLimitString(String sql, boolean hasOffset)
      Description copied from class: Dialect
      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 Dialect.getLimitString(String, int, int).

      Overrides:
      getLimitString in class Dialect
      Parameters:
      sql - The query to which to apply the limit.
      hasOffset - Is the query requesting an offset?
      Returns:
      the modified SQL

    • bindLimitParametersInReverseOrder

      public boolean bindLimitParametersInReverseOrder()
      Description copied from class: Dialect
      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?
      Overrides:
      bindLimitParametersInReverseOrder in class Dialect
      Returns:
      true if the correct order is limit, offset

    • bindLimitParametersFirst

      public boolean bindLimitParametersFirst()
      Description copied from class: Dialect
      Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?
      Overrides:
      bindLimitParametersFirst in class Dialect
      Returns:
      true if limit parameters should come before other parameters

    • supportsIfExistsAfterTableName

      public boolean supportsIfExistsAfterTableName()
      Overrides:
      supportsIfExistsAfterTableName in class Dialect

    • supportsSequences

      public boolean supportsSequences()
      Description copied from class: Dialect
      Does this dialect support sequences?
      Overrides:
      supportsSequences in class Dialect
      Returns:
      True if sequences supported; false otherwise.

    • supportsPooledSequences

      public boolean supportsPooledSequences()
      Description copied from class: Dialect
      Does this dialect support "pooled" sequences. Not aware of a better name for this. Essentially can we specify the initial and increment values?
      Overrides:
      supportsPooledSequences in class Dialect
      Returns:
      True if such "pooled" sequences are supported; false otherwise.
      See Also:

    • getCreateSequenceString

      public String getCreateSequenceString(String sequenceName)
      Description copied from class: Dialect
      Typically dialects which support sequences can create a sequence with a single command. This is convenience form of Dialect.getCreateSequenceStrings(java.lang.String) 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 Dialect.getCreateSequenceStrings(java.lang.String).

      Overrides:
      getCreateSequenceString in class Dialect
      Parameters:
      sequenceName - The name of the sequence
      Returns:
      The sequence creation command

    • getDropSequenceString

      public String getDropSequenceString(String sequenceName)
      Description copied from class: Dialect
      Typically dialects which support sequences can drop a sequence with a single command. This is convenience form of Dialect.getDropSequenceStrings(java.lang.String) 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 Dialect.getDropSequenceStrings(java.lang.String).

      Overrides:
      getDropSequenceString in class Dialect
      Parameters:
      sequenceName - The name of the sequence
      Returns:
      The sequence drop commands

    • getSelectSequenceNextValString

      public String getSelectSequenceNextValString(String sequenceName)
      Description copied from class: Dialect
      Generate the select expression fragment that will retrieve the next value of a sequence as part of another (typically DML) statement.

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

      Overrides:
      getSelectSequenceNextValString in class Dialect
      Parameters:
      sequenceName - the name of the sequence
      Returns:
      The "nextval" fragment.

    • getSequenceNextValString

      public String getSequenceNextValString(String sequenceName)
      Description copied from class: Dialect
      Generate the appropriate select statement to to retrieve the next value of a sequence.

      This should be a "stand alone" select statement.

      Overrides:
      getSequenceNextValString in class Dialect
      Parameters:
      sequenceName - the name of the sequence
      Returns:
      String The "nextval" select string.

    • getQuerySequencesString

      public String getQuerySequencesString()
      Description copied from class: Dialect
      Get the select command used retrieve the names of all sequences.
      Overrides:
      getQuerySequencesString in class Dialect
      Returns:
      The select command; or null if sequences are not supported.
      See Also:

    • getViolatedConstraintNameExtracter

      public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter()
      Overrides:
      getViolatedConstraintNameExtracter in class Dialect

    • supportsTemporaryTables

      public boolean supportsTemporaryTables()
      Description copied from class: Dialect
      Does this dialect support temporary tables?
      Overrides:
      supportsTemporaryTables in class Dialect
      Returns:
      True if temp tables are supported; false otherwise.

    • getCreateTemporaryTableString

      public String getCreateTemporaryTableString()
      Description copied from class: Dialect
      Command used to create a temporary table.
      Overrides:
      getCreateTemporaryTableString in class Dialect
      Returns:
      The command used to create a temporary table.

    • performTemporaryTableDDLInIsolation

      public Boolean performTemporaryTableDDLInIsolation()
      Description copied from class: Dialect
      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 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:

      Overrides:
      performTemporaryTableDDLInIsolation in class Dialect
      Returns:
      see the result matrix above.

    • dropTemporaryTableAfterUse

      public boolean dropTemporaryTableAfterUse()
      Description copied from class: Dialect
      Do we need to drop the temporary table after use?
      Overrides:
      dropTemporaryTableAfterUse in class Dialect
      Returns:
      True if the table should be dropped.

    • supportsCurrentTimestampSelection

      public boolean supportsCurrentTimestampSelection()
      Description copied from class: Dialect
      Does this dialect support a way to retrieve the database's current timestamp value?
      Overrides:
      supportsCurrentTimestampSelection in class Dialect
      Returns:
      True if the current timestamp can be retrieved; false otherwise.

    • isCurrentTimestampSelectStringCallable

      public boolean isCurrentTimestampSelectStringCallable()
      Description copied from class: Dialect
      Should the value returned by Dialect.getCurrentTimestampSelectString() be treated as callable. Typically this indicates that JDBC escape syntax is being used...
      Overrides:
      isCurrentTimestampSelectStringCallable in class Dialect
      Returns:
      True if the Dialect.getCurrentTimestampSelectString() return is callable; false otherwise.

    • getCurrentTimestampSelectString

      public String getCurrentTimestampSelectString()
      Description copied from class: Dialect
      Retrieve the command used to retrieve the current timestamp from the database.
      Overrides:
      getCurrentTimestampSelectString in class Dialect
      Returns:
      The command.

    • supportsUnionAll

      public boolean supportsUnionAll()
      Description copied from class: Dialect
      Does this dialect support UNION ALL, which is generally a faster variant of UNION?
      Overrides:
      supportsUnionAll in class Dialect
      Returns:
      True if UNION ALL is supported; false otherwise.

    • supportsLobValueChangePropogation

      public boolean supportsLobValueChangePropogation()
      Description copied from class: Dialect
      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: Blob.setBinaryStream(long), Blob.setBytes(long, byte[]), Blob.setBytes(long, byte[], int, int), or Blob.truncate(long).

      For CLOBs, the internal value might be changed by: Clob.setAsciiStream(long), Clob.setCharacterStream(long), Clob.setString(long, String), Clob.setString(long, String, int, int), or 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 Dialect.supportsExpectedLobUsagePattern().

      Overrides:
      supportsLobValueChangePropogation in class Dialect
      Returns:
      True if the changes are propagated back to the database; false otherwise.

    • supportsTupleDistinctCounts

      public boolean supportsTupleDistinctCounts()
      Description copied from class: Dialect
      Does this dialect support `count(distinct a,b)`?
      Overrides:
      supportsTupleDistinctCounts in class Dialect
      Returns:
      True if the database supports counting disintct tuples; false otherwise.

    • doesReadCommittedCauseWritersToBlockReaders

      public boolean doesReadCommittedCauseWritersToBlockReaders()
      Description copied from class: Dialect
      For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released?
      Overrides:
      doesReadCommittedCauseWritersToBlockReaders in class Dialect
      Returns:
      True if writers block readers to achieve READ_COMMITTED; false otherwise.