org.datanucleus.store.rdbms.sql

Class SQLStatement

java.lang.Object

org.datanucleus.store.rdbms.sql.SQLStatement

Direct Known Subclasses:

DeleteStatement, InsertStatement, SelectStatement, UpdateStatement

public abstract class SQLStatement
extends Object

Class providing an API for generating SQL statements. Caller should create the SQLStatement object and (optionally) call setClassLoaderResolver() to set any class loading restriction. Then the caller builds up the statement using the various methods, and accesses the SQL statement using getSQLText().

The generated SQL is cached. Any use of a mutating method, changing the composition of the statement will clear the cached SQL, and it will be regenerated when

getSQLText

is called next.

Table Groups

When tables are registered in the statement they are split into "table groups". A table group is, in simple terms, an object in the query. If a table has a super-table and a field of the object is selected that is in the super-table then the super-table is added to the table group. If there is a join to a related object then the table of this object will be put in a new table group. So the same datastore table can appear multiple times in the statement, each time for a different object.

Table Aliases

All methods that cause a new SQLTable to be created also allow specification of the table alias in the statement. Where the alias is not provided then we use a table "namer" (definable on the plugin-point "org.datanucleus.store.rdbms.sql_tablenamer"). The table namer can define names simply based on the table number, or based on table group and the number of tables in the group etc etc. To select a particular table "namer", set the extension "table-naming-strategy" to the key of the namer plugin. The default is "alpha-scheme" which bases table names on the group and number in that group. Note that this class is not intended to be thread-safe. It is used by a single ExecutionContext

Field Summary

Fields

Modifier and Type	Field and Description
protected String	candidateClassName Name of class that this statement selects (optional, only typically for unioned statements).
protected org.datanucleus.ClassLoaderResolver	clr ClassLoader resolver to use.
static String	EXTENSION_LOCK_FOR_UPDATE
static String	EXTENSION_LOCK_FOR_UPDATE_NOWAIT
static String	EXTENSION_SQL_TABLE_NAMING_STRATEGY
protected Map<String,Object>	extensions Map of extensions for use in generating the SQL, keyed by the extension name.
protected List<SQLJoin>	joins List of joins for this statement.
protected SQLTableNamer	namer
protected SQLStatement	parent Parent statement, if this is a subquery SELECT.
protected SQLTable	primaryTable Primary table for this statement.
protected QueryGenerator	queryGenerator Context of any query generation.
protected RDBMSStoreManager	rdbmsMgr Manager for the RDBMS datastore.
protected boolean	requiresJoinReorder
protected SQLText	sql Cached SQL statement, generated by getSQLText().
protected Map<String,SQLTableGroup>	tableGroups Map of table groups keyed by the group name.
protected static Map<String,SQLTableNamer>	tableNamerByName Map of SQLTable naming instance keyed by the name of the naming scheme.
protected Map<String,SQLTable>	tables Map of tables referenced in this statement, keyed by their alias.
protected BooleanExpression	where Where clause.

Constructor Summary

Constructors

Constructor and Description
SQLStatement(SQLStatement parentStmt, RDBMSStoreManager rdbmsMgr, Table table, DatastoreIdentifier alias, String tableGroupName, Map<String,Object> extensions) Constructor for an SQL statement that is a subquery of another statement.

Method Summary

Modifier and Type	Method and Description
void	addAndConditionToJoinForTable(SQLTable sqlTbl, BooleanExpression andCondition, boolean applyToUnions) Method to find the JOIN for the specified table and add the specified 'and' condition to the JOIN as an 'ON' clause.
void	addExtension(String key, Object value) Method to define an extension for this query statement allowing control over its behaviour in generating a query.
protected void	addJoin(SQLJoin.JoinType joinType, SQLTable sourceTable, SQLTable targetTable, BooleanExpression joinCondition, SQLJoin parentJoin) Internal method to form a join to the specified table using the provided mappings.
String	getCandidateClassName()
org.datanucleus.ClassLoaderResolver	getClassLoaderResolver()
DatastoreAdapter	getDatastoreAdapter()
protected BooleanExpression	getJoinConditionForJoin(SQLTable sourceTable, JavaTypeMapping sourceMapping, JavaTypeMapping sourceParentMapping, SQLTable targetTable, JavaTypeMapping targetMapping, JavaTypeMapping targetParentMapping, Object[] discrimValues) Convenience method to generate the join condition between source and target tables for the supplied mappings.
SQLJoin	getJoinForTable(SQLTable sqlTbl) Accessor for the type of join used for the specified table.
SQLJoin.JoinType	getJoinTypeForTable(SQLTable sqlTbl) Accessor for the type of join used for the specified table.
int	getNumberOfTableGroups() Accessor for the number of table groups.
int	getNumberOfTables() Accessor for the number of tables defined for this statement.
SQLStatement	getParentStatement()
SQLTable	getPrimaryTable() Accessor for the primary table of the statement.
QueryGenerator	getQueryGenerator()
RDBMSStoreManager	getRDBMSManager()
SQLExpressionFactory	getSQLExpressionFactory()
SQLText	getSQLText()
SQLTable	getTable(String alias) Accessor for the SQLTable object with the specified alias (if defined for this statement).
SQLTable	getTable(Table table, String groupName) Accessor for the SQLTable object for the specified table (if defined for this statement) in the specified table group.
SQLTable	getTableForDatastoreContainer(Table table) Convenience method to find a registered SQLTable that is for the specified table
SQLTableGroup	getTableGroup(String groupName) Accessor for the table group with this name.
protected SQLTableNamer	getTableNamer(String namingSchema) Method to return the namer for a particular schema.
Object	getValueForExtension(String key) Accessor for the value for an extension.
protected void	invalidateStatement() Method to uncache the generated SQL (because some condition has changed).
boolean	isChildStatementOf(SQLStatement stmt) Convenience method to return if this statement is a child (inner) statement of the supplied statement.
SQLTable	join(SQLJoin.JoinType joinType, SQLTable sourceTable, JavaTypeMapping sourceMapping, JavaTypeMapping sourceParentMapping, Table target, String targetAlias, JavaTypeMapping targetMapping, JavaTypeMapping targetParentMapping, Object[] discrimValues, String tableGrpName, boolean applyToUnions, SQLJoin parentJoin) Method to form a join to the specified table using the provided mappings, with the join condition derived from the source-target mappings.
SQLTable	join(SQLJoin.JoinType joinType, SQLTable sourceTable, JavaTypeMapping sourceMapping, Table target, String targetAlias, JavaTypeMapping targetMapping, Object[] discrimValues, String tableGrpName) Method to form a join to the specified table using the provided mappings, with the join also being applied to any UNIONed statements.
SQLTable	join(SQLJoin.JoinType joinType, SQLTable sourceTable, JavaTypeMapping sourceMapping, Table target, String targetAlias, JavaTypeMapping targetMapping, Object[] discrimValues, String tableGrpName, boolean applyToUnions) Method to form a join to the specified table using the provided mappings.
SQLTable	join(SQLJoin.JoinType joinType, SQLTable sourceTable, JavaTypeMapping sourceMapping, Table target, String targetAlias, JavaTypeMapping targetMapping, Object[] discrimValues, String tableGrpName, boolean applyToUnions, SQLJoin parentJoin) Method to form a join to the specified table using the provided mappings.
SQLTable	join(SQLJoin.JoinType joinType, SQLTable sourceTable, JavaTypeMapping sourceMapping, Table target, String targetAlias, JavaTypeMapping targetMapping, Object[] discrimValues, String tableGrpName, SQLJoin parentJoin) Method to form a join to the specified table using the provided mappings, with the join also being applied to any UNIONed statements.
SQLTable	join(SQLJoin.JoinType joinType, SQLTable sourceTable, Table target, String targetAlias, String tableGrpName, BooleanExpression joinCondition, boolean applyToUnions) Method to form a join to the specified table using the provided mappings and applying the provided join condition (rather than generating one from the source/target mappings).
void	log(org.datanucleus.util.NucleusLogger logger) Method to dump the statement to the supplied log (debug level).
protected void	putSQLTableInGroup(SQLTable sqlTbl, String groupName, SQLJoin.JoinType joinType) Convenience method to add the SQLTable to the specified group.
String	removeCrossJoin(SQLTable targetSqlTbl) Method to remove a cross join for the specified table (if joined via cross join).
void	setCandidateClassName(String name)
void	setClassLoaderResolver(org.datanucleus.ClassLoaderResolver clr)
void	setQueryGenerator(QueryGenerator gen)
void	whereAnd(BooleanExpression expr, boolean applyToUnions) Method to add an AND condition to the WHERE clause.
void	whereOr(BooleanExpression expr, boolean applyToUnions) Method to add an OR condition to the WHERE clause.

Methods inherited from class java.lang.Object

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

Field Detail

EXTENSION_SQL_TABLE_NAMING_STRATEGY

public static final String EXTENSION_SQL_TABLE_NAMING_STRATEGY

See Also:

Constant Field Values

EXTENSION_LOCK_FOR_UPDATE

public static final String EXTENSION_LOCK_FOR_UPDATE

See Also:

Constant Field Values

EXTENSION_LOCK_FOR_UPDATE_NOWAIT

public static final String EXTENSION_LOCK_FOR_UPDATE_NOWAIT

See Also:

Constant Field Values

tableNamerByName

protected static final Map<String,SQLTableNamer> tableNamerByName

Map of SQLTable naming instance keyed by the name of the naming scheme.

sql

protected SQLText sql

Cached SQL statement, generated by getSQLText().

rdbmsMgr

protected RDBMSStoreManager rdbmsMgr

Manager for the RDBMS datastore.

clr

protected org.datanucleus.ClassLoaderResolver clr

ClassLoader resolver to use. Used by sub-expressions. Defaults to the loader resolver for the store manager.

queryGenerator

protected QueryGenerator queryGenerator

Context of any query generation.

namer

protected SQLTableNamer namer

candidateClassName

protected String candidateClassName

Name of class that this statement selects (optional, only typically for unioned statements).

extensions

protected Map<String,Object> extensions

Map of extensions for use in generating the SQL, keyed by the extension name.

parent

protected SQLStatement parent

Parent statement, if this is a subquery SELECT. Must be set at construction.

primaryTable

protected SQLTable primaryTable

Primary table for this statement.

joins

protected List<SQLJoin> joins

List of joins for this statement.

requiresJoinReorder

protected boolean requiresJoinReorder

tables

protected Map<String,SQLTable> tables

Map of tables referenced in this statement, keyed by their alias. Note that these aliases are in the input case.

tableGroups

protected Map<String,SQLTableGroup> tableGroups

Map of table groups keyed by the group name.

where

protected BooleanExpression where

Where clause.

Constructor Detail

SQLStatement

public SQLStatement(SQLStatement parentStmt,
                    RDBMSStoreManager rdbmsMgr,
                    Table table,
                    DatastoreIdentifier alias,
                    String tableGroupName,
                    Map<String,Object> extensions)

Constructor for an SQL statement that is a subquery of another statement.

Parameters:

parentStmt - Parent statement

rdbmsMgr - The datastore manager

table - The primary table

alias - Alias for this table

tableGroupName - Name of candidate table-group (if any). Uses "Group0" if not provided

extensions - Any extensions (optional)

Method Detail

getRDBMSManager

public RDBMSStoreManager getRDBMSManager()

setClassLoaderResolver

public void setClassLoaderResolver(org.datanucleus.ClassLoaderResolver clr)

getClassLoaderResolver

public org.datanucleus.ClassLoaderResolver getClassLoaderResolver()

setCandidateClassName

public void setCandidateClassName(String name)

getCandidateClassName

public String getCandidateClassName()

getQueryGenerator

public QueryGenerator getQueryGenerator()

setQueryGenerator

public void setQueryGenerator(QueryGenerator gen)

getSQLExpressionFactory

public SQLExpressionFactory getSQLExpressionFactory()

getDatastoreAdapter

public DatastoreAdapter getDatastoreAdapter()

getParentStatement

public SQLStatement getParentStatement()

isChildStatementOf

public boolean isChildStatementOf(SQLStatement stmt)

Convenience method to return if this statement is a child (inner) statement of the supplied statement.

Parameters:

stmt - The statement that may be parent, grandparent etc of this statement

Returns:

Whether this is a child of the supplied statement

addExtension

public void addExtension(String key,
                         Object value)

Method to define an extension for this query statement allowing control over its behaviour in generating a query.

Parameters:

key - Extension key

value - Value for the key

getValueForExtension

public Object getValueForExtension(String key)

Accessor for the value for an extension.

Parameters:

key - Key for the extension

Returns:

Value for the extension (if any)

getPrimaryTable

public SQLTable getPrimaryTable()

Accessor for the primary table of the statement.

Returns:

The primary table

getTable

public SQLTable getTable(String alias)

Accessor for the SQLTable object with the specified alias (if defined for this statement). Note that this alias should be in the same case as what they were defined to the statement as.

Parameters:

alias - Alias

Returns:

The SQLTable

getTableForDatastoreContainer

public SQLTable getTableForDatastoreContainer(Table table)

Convenience method to find a registered SQLTable that is for the specified table

Parameters:

table - The table

Returns:

The SQLTable (or null if not referenced)

getTable

public SQLTable getTable(Table table,
                         String groupName)

Accessor for the SQLTable object for the specified table (if defined for this statement) in the specified table group.

Parameters:

table - The table

groupName - Name of the table group where we should look for this table

Returns:

The SQLTable (if found)

getTableGroup

public SQLTableGroup getTableGroup(String groupName)

Accessor for the table group with this name.

Parameters:

groupName - Name of the group

Returns:

The table group

getNumberOfTableGroups

public int getNumberOfTableGroups()

Accessor for the number of table groups.

Returns:

Number of table groups (including that of the candidate)

getNumberOfTables

public int getNumberOfTables()

Accessor for the number of tables defined for this statement.

Returns:

Number of tables (in addition to the primary table)

join

public SQLTable join(SQLJoin.JoinType joinType,
                     SQLTable sourceTable,
                     JavaTypeMapping sourceMapping,
                     Table target,
                     String targetAlias,
                     JavaTypeMapping targetMapping,
                     Object[] discrimValues,
                     String tableGrpName)

Method to form a join to the specified table using the provided mappings, with the join also being applied to any UNIONed statements.

Parameters:

joinType - Type of join.

sourceTable - SQLTable for the source (null implies primaryTable)

sourceMapping - Mapping in this table to join from

target - Table to join to

targetAlias - Alias for the target table (if known)

targetMapping - Mapping in the other table to join to (also defines the table to join to)

discrimValues - Any discriminator values to apply for the joined table (null if not)

tableGrpName - Name of the table group for the target (null implies a new group)

Returns:

SQLTable for the target

join

public SQLTable join(SQLJoin.JoinType joinType,
                     SQLTable sourceTable,
                     JavaTypeMapping sourceMapping,
                     Table target,
                     String targetAlias,
                     JavaTypeMapping targetMapping,
                     Object[] discrimValues,
                     String tableGrpName,
                     SQLJoin parentJoin)

Method to form a join to the specified table using the provided mappings, with the join also being applied to any UNIONed statements.

Parameters:

joinType - Type of join.

sourceTable - SQLTable for the source (null implies primaryTable)

sourceMapping - Mapping in this table to join from

target - Table to join to

targetAlias - Alias for the target table (if known)

targetMapping - Mapping in the other table to join to (also defines the table to join to)

discrimValues - Any discriminator values to apply for the joined table (null if not)

tableGrpName - Name of the table group for the target (null implies a new group)

parentJoin - Parent join when this join will be a sub-join (part of "join grouping")

Returns:

SQLTable for the target

join

public SQLTable join(SQLJoin.JoinType joinType,
                     SQLTable sourceTable,
                     JavaTypeMapping sourceMapping,
                     Table target,
                     String targetAlias,
                     JavaTypeMapping targetMapping,
                     Object[] discrimValues,
                     String tableGrpName,
                     boolean applyToUnions)

Method to form a join to the specified table using the provided mappings.

Parameters:

joinType - Type of join.

sourceTable - SQLTable for the source (null implies primaryTable)

sourceMapping - Mapping in this table to join from

target - Table to join to

targetAlias - Alias for the target table (if known)

targetMapping - Mapping in the other table to join to (also defines the table to join to)

discrimValues - Any discriminator values to apply for the joined table (null if not)

tableGrpName - Name of the table group for the target (null implies a new group)

applyToUnions - Whether to apply to any unioned statements (only applies to SELECT statements)

Returns:

SQLTable for the target

join

public SQLTable join(SQLJoin.JoinType joinType,
                     SQLTable sourceTable,
                     JavaTypeMapping sourceMapping,
                     Table target,
                     String targetAlias,
                     JavaTypeMapping targetMapping,
                     Object[] discrimValues,
                     String tableGrpName,
                     boolean applyToUnions,
                     SQLJoin parentJoin)

Method to form a join to the specified table using the provided mappings.

Parameters:

joinType - Type of join.

sourceTable - SQLTable for the source (null implies primaryTable)

sourceMapping - Mapping in this table to join from

target - Table to join to

targetAlias - Alias for the target table (if known)

targetMapping - Mapping in the other table to join to (also defines the table to join to)

discrimValues - Any discriminator values to apply for the joined table (null if not)

tableGrpName - Name of the table group for the target (null implies a new group)

applyToUnions - Whether to apply to any unioned statements (only applies to SELECT statements)

parentJoin - Parent join when this join will be a sub-join (part of "join grouping")

Returns:

SQLTable for the target

join

public SQLTable join(SQLJoin.JoinType joinType,
                     SQLTable sourceTable,
                     JavaTypeMapping sourceMapping,
                     JavaTypeMapping sourceParentMapping,
                     Table target,
                     String targetAlias,
                     JavaTypeMapping targetMapping,
                     JavaTypeMapping targetParentMapping,
                     Object[] discrimValues,
                     String tableGrpName,
                     boolean applyToUnions,
                     SQLJoin parentJoin)

Method to form a join to the specified table using the provided mappings, with the join condition derived from the source-target mappings.

Parameters:

joinType - Type of join.

sourceTable - SQLTable for the source (null implies primaryTable)

sourceMapping - Mapping in this table to join from

sourceParentMapping - Optional, if this source mapping is a sub mapping (e.g interface impl).

target - Table to join to

targetAlias - Alias for the target table (if known)

targetMapping - Mapping in the other table to join to (also defines the table to join to)

targetParentMapping - Optional, if this source mapping is a sub mapping (e.g interface impl).

discrimValues - Any discriminator values to apply for the joined table (null if not)

tableGrpName - Name of the table group for the target (null implies a new group)

applyToUnions - Whether to apply to any unioned statements (only applies to SELECT statements)

parentJoin - Parent join when this join will be a sub-join (part of "join grouping")

Returns:

SQLTable for the target

join

public SQLTable join(SQLJoin.JoinType joinType,
                     SQLTable sourceTable,
                     Table target,
                     String targetAlias,
                     String tableGrpName,
                     BooleanExpression joinCondition,
                     boolean applyToUnions)

Method to form a join to the specified table using the provided mappings and applying the provided join condition (rather than generating one from the source/target mappings). This is used with JPQL where we allow two root entities to be joined using a provide "ON" condition.

Parameters:

joinType - Type of join.

sourceTable - SQLTable for the source (null implies primaryTable)

target - Table to join to

targetAlias - Alias for the target table (if known)

tableGrpName - Name of the table group for the target (null implies a new group)

joinCondition - On clause for the join

applyToUnions - Whether to apply to any unioned statements (only applies to SELECT statements)

Returns:

SQLTable for the target

getJoinTypeForTable

public SQLJoin.JoinType getJoinTypeForTable(SQLTable sqlTbl)

Accessor for the type of join used for the specified table.

Parameters:

sqlTbl - The table to check

Returns:

The join type, or null if not joined in this statement

addAndConditionToJoinForTable

public void addAndConditionToJoinForTable(SQLTable sqlTbl,
                                          BooleanExpression andCondition,
                                          boolean applyToUnions)

Method to find the JOIN for the specified table and add the specified 'and' condition to the JOIN as an 'ON' clause.

Parameters:

sqlTbl - The table

andCondition - The 'ON' condition to add

applyToUnions - Whether to apply to unions (see SelectStatement)

getJoinForTable

public SQLJoin getJoinForTable(SQLTable sqlTbl)

Accessor for the type of join used for the specified table.

Parameters:

sqlTbl - The table to check

Returns:

The join type, or null if not joined in this statement

removeCrossJoin

public String removeCrossJoin(SQLTable targetSqlTbl)

Method to remove a cross join for the specified table (if joined via cross join). Also removes the table from the list of tables. This is called where we have bound a variable via a CROSS JOIN (in the absence of better information) and found out later it could become an INNER JOIN. If the supplied table is not joined via a cross join then does nothing.

Parameters:

targetSqlTbl - The table to drop the cross join for

Returns:

The removed alias

putSQLTableInGroup

protected void putSQLTableInGroup(SQLTable sqlTbl,
                                  String groupName,
                                  SQLJoin.JoinType joinType)

Convenience method to add the SQLTable to the specified group. If the group doesn't yet exist then it adds it.

Parameters:

sqlTbl - SQLTable to add

groupName - The group

joinType - type of join to start this table group

addJoin

protected void addJoin(SQLJoin.JoinType joinType,
                       SQLTable sourceTable,
                       SQLTable targetTable,
                       BooleanExpression joinCondition,
                       SQLJoin parentJoin)

Internal method to form a join to the specified table using the provided mappings.

Parameters:

joinType - Type of join (INNER, LEFT OUTER, RIGHT OUTER, CROSS, NON-ANSI)

sourceTable - SQLTable to join from

targetTable - SQLTable to join to

joinCondition - Condition for the join

parentJoin - Optional parent join (which will mean this join becomes a sub-join)

getJoinConditionForJoin

protected BooleanExpression getJoinConditionForJoin(SQLTable sourceTable,
                                                    JavaTypeMapping sourceMapping,
                                                    JavaTypeMapping sourceParentMapping,
                                                    SQLTable targetTable,
                                                    JavaTypeMapping targetMapping,
                                                    JavaTypeMapping targetParentMapping,
                                                    Object[] discrimValues)

Convenience method to generate the join condition between source and target tables for the supplied mappings.

Parameters:

sourceTable - Source table

sourceMapping - Mapping in source table

sourceParentMapping - Optional parent of this source mapping (if joining an impl of an interface)

targetTable - Target table

targetMapping - Mapping in target table

targetParentMapping - Optional parent of this target mapping (if joining an impl of an interface)

discrimValues - Optional discriminator values to further restrict

Returns:

The join condition

getTableNamer

protected SQLTableNamer getTableNamer(String namingSchema)

Method to return the namer for a particular schema. If there is no instantiated namer for this schema then instantiates one.

Parameters:

namingSchema - Table naming schema to use

Returns:

The namer

whereAnd

public void whereAnd(BooleanExpression expr,
                     boolean applyToUnions)

Method to add an AND condition to the WHERE clause.

Parameters:

expr - The condition

applyToUnions - whether to apply this and to any UNIONs in the statement (only applies to SELECT statements)

whereOr

public void whereOr(BooleanExpression expr,
                    boolean applyToUnions)

Method to add an OR condition to the WHERE clause.

Parameters:

expr - The condition

applyToUnions - Whether to apply to unions (only applies to SELECT statements)

getSQLText

public SQLText getSQLText()

invalidateStatement

protected void invalidateStatement()

Method to uncache the generated SQL (because some condition has changed).

log

public void log(org.datanucleus.util.NucleusLogger logger)

Method to dump the statement to the supplied log (debug level). Logs the SQL that this statement equates to, and the TableGroup(s) and their associated tables.

Parameters:

logger - The logger