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MySQLDialect (Hibernate API Documentation) - Hibernate 3.2.3 正式版 API 英文文档

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org.hibernate.dialect
Class MySQLDialect

java.lang.Object
  org.hibernate.dialect.Dialect
      org.hibernate.dialect.MySQLDialect

Direct Known Subclasses:

MySQL5Dialect, MySQLInnoDBDialect, MySQLMyISAMDialect

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public class MySQLDialect

extends Dialect

An SQL dialect for MySQL (prior to 5.x).

Author:

Gavin King

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Field Summary

 

Fields inherited from class org.hibernate.dialect.Dialect

CLOSED_QUOTE, DEFAULT_BATCH_SIZE, NO_BATCH, QUOTE

 

Constructor Summary

MySQLDialect()

 

Method Summary
boolean	areStringComparisonsCaseInsensitive()           Are string comparisons implicitly case insensitive.
char	closeQuote()           The character specific to this dialect used to close a quoted identifier.
String	getAddColumnString()           The syntax used to add a column to a table (optional).
String	getAddForeignKeyConstraintString(String constraintName, String[] foreignKey, String referencedTable, String[] primaryKey, boolean referencesPrimaryKey)           The syntax used to add a foreign key constraint to a table.
String	getCastTypeName(int code)           Get the name of the database type appropriate for casting operations (via the CAST() SQL function) for the given Types typecode.
String	getColumnComment(String comment)
String	getCreateTemporaryTableString()           Command used to create a temporary table.
String	getCurrentTimestampSelectString()           Retrieve the command used to retrieve the current timestammp from the database.
String	getDropForeignKeyString()
String	getIdentityColumnString()           The syntax used during DDL to define a column as being an IDENTITY.
String	getIdentitySelectString()           Get the select command to use to retrieve the last generated IDENTITY value.
String	getLimitString(String sql, boolean hasOffset)           Apply s limit clause to the query.
ResultSet	getResultSet(CallableStatement ps)           Given a callable statement previously processed by registerResultSetOutParameter(java.sql.CallableStatement, int), extract the ResultSet from the OUT parameter.
String	getSelectGUIDString()           Get the command used to select a GUID from the underlying database.
String	getTableComment(String comment)
boolean	isCurrentTimestampSelectStringCallable()           Should the value returned by getCurrentTimestampSelectString() be treated as callable.
char	openQuote()           The character specific to this dialect used to begin a quoted identifier.
Boolean	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.
boolean	qualifyIndexName()           Do we need to qualify index names with the schema name?
int	registerResultSetOutParameter(CallableStatement statement, int col)           Registers an OUT parameter which will be returing a ResultSet.
protected  void	registerVarcharTypes()
boolean	supportsCascadeDelete()
boolean	supportsCurrentTimestampSelection()           Does this dialect support a way to retrieve the database's current timestamp value?
boolean	supportsEmptyInList()           Does this dialect support empty IN lists? For example, is [where XYZ in ()] a supported construct?
boolean	supportsIdentityColumns()           Does this dialect support identity column key generation?
boolean	supportsIfExistsBeforeTableName()
boolean	supportsLimit()           Does this dialect support some form of limiting query results via a SQL clause?
boolean	supportsLobValueChangePropogation()           Does the dialect support propogating 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...
boolean	supportsRowValueConstructorSyntax()           Is this dialect known to support what ANSI-SQL terms "row value constructor" syntax; sometimes called tuple syntax.
boolean	supportsSubqueryOnMutatingTable()           Does this dialect support referencing the table being mutated in a subquery.
boolean	supportsTemporaryTables()           Does this dialect support temporary tables?

 

Methods inherited from class org.hibernate.dialect.Dialect

appendIdentitySelectToInsert, appendLockHint, applyLocksToSql, bindLimitParametersFirst, bindLimitParametersInReverseOrder, buildSQLExceptionConverter, createCaseFragment, createOuterJoinFragment, doesReadCommittedCauseWritersToBlockReaders, doesRepeatableReadCauseReadersToBlockWriters, dropConstraints, dropTemporaryTableAfterUse, forUpdateOfColumns, generateTemporaryTableName, getAddPrimaryKeyConstraintString, getCascadeConstraintsString, getCreateMultisetTableString, getCreateSequenceString, getCreateSequenceString, getCreateSequenceStrings, getCreateSequenceStrings, getCreateTableString, getCreateTemporaryTablePostfix, getCurrentTimestampSQLFunctionName, getDefaultProperties, getDialect, getDialect, getDropSequenceString, getDropSequenceStrings, getForUpdateNowaitString, getForUpdateNowaitString, getForUpdateString, getForUpdateString, getForUpdateString, getFunctions, getHibernateTypeName, getHibernateTypeName, getIdentityColumnString, getIdentityInsertString, getIdentitySelectString, getKeywords, getLimitString, getLockingStrategy, getLowercaseFunction, getMaxAliasLength, getNativeIdentifierGeneratorClass, getNoColumnsInsertString, getNullColumnString, getQuerySequencesString, getSelectClauseNullString, getSelectSequenceNextValString, getSequenceNextValString, getTableTypeString, getTypeName, getTypeName, getViolatedConstraintNameExtracter, hasAlterTable, hasDataTypeInIdentityColumn, hasSelfReferentialForeignKeyBug, quote, registerColumnType, registerColumnType, registerFunction, registerHibernateType, registerHibernateType, registerKeyword, supportsBindAsCallableArgument, supportsCircularCascadeDeleteConstraints, supportsColumnCheck, supportsCommentOn, supportsExistsInSelect, supportsExpectedLobUsagePattern, supportsIfExistsAfterTableName, supportsInsertSelectIdentity, supportsLimitOffset, supportsNotNullUnique, supportsOuterJoinForUpdate, supportsParametersInInsertSelect, supportsPooledSequences, supportsResultSetPositionQueryMethodsOnForwardOnlyCursor, supportsRowValueConstructorSyntaxInInList, supportsSequences, supportsSubselectAsInPredicateLHS, supportsTableCheck, supportsUnboundedLobLocatorMaterialization, supportsUnionAll, supportsUnique, supportsUniqueConstraintInCreateAlterTable, supportsVariableLimit, toBooleanValueString, toString, transformSelectString, useInputStreamToInsertBlob, useMaxForLimit

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Constructor Detail

MySQLDialect

public MySQLDialect()

Method Detail

registerVarcharTypes

protected void registerVarcharTypes()

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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.

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qualifyIndexName

public boolean qualifyIndexName()

Description copied from class: Dialect

Do we need to qualify index names with the schema name?

Overrides:

qualifyIndexName in class Dialect

Returns:

boolean

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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.

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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

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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.

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getAddForeignKeyConstraintString

public String getAddForeignKeyConstraintString(String constraintName,
                                               String[] foreignKey,
                                               String referencedTable,
                                               String[] primaryKey,
                                               boolean referencesPrimaryKey)

Description copied from class: Dialect

The syntax used to add a foreign key constraint to a table.

Overrides:

getAddForeignKeyConstraintString in class Dialect

Parameters:

constraintName - The FK constraint name.

foreignKey - The names of the columns comprising the FK

referencedTable - The table referenced by the FK

primaryKey - The explicit columns in the referencedTable referenced by this FK.

referencesPrimaryKey - if false, constraint should be explicit about which column names the constraint refers to

Returns:

the "add FK" fragment

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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.

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getDropForeignKeyString

public String getDropForeignKeyString()

Overrides:

getDropForeignKeyString in class Dialect

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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 caluses 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

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closeQuote

public char closeQuote()

Description copied from class: Dialect

The character specific to this dialect used to close a quoted identifier.

Overrides:

closeQuote in class Dialect

Returns:

The dialect's specific close quote character.

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openQuote

public char openQuote()

Description copied from class: Dialect

The character specific to this dialect used to begin a quoted identifier.

Overrides:

openQuote in class Dialect

Returns:

The dialect's specific open quote character.

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supportsIfExistsBeforeTableName

public boolean supportsIfExistsBeforeTableName()

Overrides:

supportsIfExistsBeforeTableName in class Dialect

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getSelectGUIDString

public String getSelectGUIDString()

Description copied from class: Dialect

Get the command used to select a GUID from the underlying database.

Optional operation.

Overrides:

getSelectGUIDString in class Dialect

Returns:

The appropriate command.

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supportsCascadeDelete

public boolean supportsCascadeDelete()

Overrides:

supportsCascadeDelete in class Dialect

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getTableComment

public String getTableComment(String comment)

Overrides:

getTableComment in class Dialect

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getColumnComment

public String getColumnComment(String comment)

Overrides:

getColumnComment in class Dialect

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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.

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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.

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getCastTypeName

public String getCastTypeName(int code)

Description copied from class: Dialect

Get the name of the database type appropriate for casting operations (via the CAST() SQL function) for the given Types typecode.

Overrides:

getCastTypeName in class Dialect

Parameters:

code - The Types typecode

Returns:

The database type name

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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.

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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 sytnax is being used...

Overrides:

isCurrentTimestampSelectStringCallable in class Dialect

Returns:

True if the Dialect.getCurrentTimestampSelectString() return is callable; false otherwise.

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getCurrentTimestampSelectString

public String getCurrentTimestampSelectString()

Description copied from class: Dialect

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

Overrides:

getCurrentTimestampSelectString in class Dialect

Returns:

The command.

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registerResultSetOutParameter

public int registerResultSetOutParameter(CallableStatement statement,
                                         int col)
                                  throws SQLException

Description copied from class: Dialect

Registers an OUT parameter which will be returing a ResultSet. How this is accomplished varies greatly from DB to DB, hence its inclusion (along with Dialect.getResultSet(java.sql.CallableStatement)) here.

Overrides:

registerResultSetOutParameter in class Dialect

Parameters:

statement - The callable statement.

col - The bind position at which to register the OUT param.

Returns:

The number of (contiguous) bind positions used.

Throws:

SQLException - Indicates problems registering the OUT param.

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getResultSet

public ResultSet getResultSet(CallableStatement ps)
                       throws SQLException

Description copied from class: Dialect

Given a callable statement previously processed by Dialect.registerResultSetOutParameter(java.sql.CallableStatement, int), extract the ResultSet from the OUT parameter.

Overrides:

getResultSet in class Dialect

Parameters:

ps - The callable statement.

Returns:

The extracted result set.

Throws:

SQLException - Indicates problems extracting the result set.

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supportsRowValueConstructorSyntax

public boolean supportsRowValueConstructorSyntax()

Description copied from class: Dialect

Is this dialect known to support what ANSI-SQL terms "row value constructor" syntax; sometimes called tuple syntax.

Basically, does it support syntax like "... where (FIRST_NAME, LAST_NAME) = ('Steve', 'Ebersole') ...".

Overrides:

supportsRowValueConstructorSyntax in class Dialect

Returns:

True if this SQL dialect is known to support "row value constructor" syntax; false otherwise.

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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:

• 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 DatabaseMetaData.dataDefinitionCausesTransactionCommit()

Overrides:

performTemporaryTableDDLInIsolation in class Dialect

Returns:

see the result matrix above.

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supportsEmptyInList

public boolean supportsEmptyInList()

Description copied from class: Dialect

Does this dialect support empty IN lists?

For example, is [where XYZ in ()] a supported construct?

Overrides:

supportsEmptyInList in class Dialect

Returns:

True if empty in lists are supported; false otherwise.

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areStringComparisonsCaseInsensitive

public boolean areStringComparisonsCaseInsensitive()

Description copied from class: Dialect

Are string comparisons implicitly case insensitive.

In other words, does [where 'XYZ' = 'xyz'] resolve to true?

Overrides:

areStringComparisonsCaseInsensitive in class Dialect

Returns:

True if comparisons are case insensitive.

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supportsLobValueChangePropogation

public boolean supportsLobValueChangePropogation()

Description copied from class: Dialect

Does the dialect support propogating 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 propogated back to the database; false otherwise.

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supportsSubqueryOnMutatingTable

public boolean supportsSubqueryOnMutatingTable()

Description copied from class: Dialect

Does this dialect support referencing the table being mutated in a subquery. The "table being mutated" is the table referenced in an UPDATE or a DELETE query. And so can that table then be referenced in a subquery of said UPDATE/DELETE query.

For example, would the following two syntaxes be supported:

• delete from TABLE_A where ID not in ( select ID from TABLE_A )
• update TABLE_A set NON_ID = 'something' where ID in ( select ID from TABLE_A)

Overrides:

supportsSubqueryOnMutatingTable in class Dialect

Returns:

True if this dialect allows references the mutating table from a subquery.

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