Package org.h2.command

Class Prepared

java.lang.Object

org.h2.command.Prepared

Direct Known Subclasses:

BackupCommand, Call, DataChangeStatement, DefineCommand, ExecuteImmediate, ExecuteProcedure, Explain, Help, NoOperation, Query, ScriptBase, Set, SetSessionCharacteristics, TransactionCommand

public abstract class Prepared
extends java.lang.Object

A prepared statement.

Field Summary

Fields

Modifier and Type	Field	Description
private Command	command
protected boolean	create	Whether to create a new object (for indexes).
private java.util.List<TableView>	cteCleanups	Common table expressions (CTE) in queries require us to create temporary views, which need to be cleaned up once a command is done executing.
private long	currentRowNumber
private long	modificationMetaId
protected java.util.ArrayList<Parameter>	parameters	The list of parameters.
private int	persistedObjectId	Used to preserve object identities on database startup.
protected boolean	prepareAlways	If the query should be prepared before each execution.
private int	rowScanCount
protected SessionLocal	session	The session.
protected java.lang.String	sqlStatement	The SQL string.
protected java.util.ArrayList<Token>	sqlTokens	The SQL tokens.

Constructor Summary

Constructors

Constructor	Description
Prepared(SessionLocal session)	Create a new object.

Method Summary

Modifier and Type	Method	Description
void	checkCanceled()	Check if this statement was canceled.
protected void	checkParameters()	Check if all parameters have been set.
void	collectDependencies(java.util.HashSet<DbObject> dependencies)	Find and collect all DbObjects, this Prepared depends on.
java.util.List<TableView>	getCteCleanups()
long	getCurrentRowNumber()	Get the current row number.
(package private) long	getModificationMetaId()	Get the meta data modification id of the database when this statement was compiled.
protected int	getObjectId()	Get the current object id, or get a new id from the database.
java.util.ArrayList<Parameter>	getParameters()	Get the parameter list.
int	getPersistedObjectId()	Get the object id to use for the database object that is created in this statement.
java.lang.String	getPlanSQL(int sqlFlags)	Get the SQL statement with the execution plan.
SessionLocal	getSession()
static java.lang.String	getSimpleSQL(Expression[] list)	Get the SQL snippet of the expression list.
java.lang.String	getSQL()	Get the SQL statement.
java.util.ArrayList<Token>	getSQLTokens()	Get the SQL tokens.
abstract int	getType()	Get the command type as defined in CommandInterface
boolean	isCacheable()
boolean	isQuery()	Check if this object is a query.
boolean	isReadOnly()	Check if this command is read only.
abstract boolean	isTransactional()	Check if this command is transactional.
boolean	needRecompile()	Check if the statement needs to be re-compiled.
void	prepare()	Prepare this statement.
ResultInterface	query(long maxrows)	Execute the query.
abstract ResultInterface	queryMeta()	Get an empty result set containing the meta data.
void	setCommand(Command command)	Set the command.
void	setCteCleanups(java.util.List<TableView> cteCleanups)	Set the temporary views created for CTE's.
void	setCurrentRowNumber(long rowNumber)	Set the current row number.
(package private) void	setModificationMetaId(long id)	Set the meta data modification id of this statement.
void	setParameterList(java.util.ArrayList<Parameter> parameters)	Set the parameter list of this statement.
void	setPersistedObjectId(int i)	Set the persisted object id for this statement.
void	setPrepareAlways(boolean prepareAlways)	Set the prepare always flag.
private void	setProgress()	Notifies query progress via the DatabaseEventListener
protected DbException	setRow(DbException e, long rowId, java.lang.String values)	Set the SQL statement of the exception to the given row.
void	setSession(SessionLocal currentSession)	Set the session for this statement.
void	setSQL(java.lang.String sql, java.util.ArrayList<Token> sqlTokens)	Set the SQL statement.
java.lang.String	toString()	Convert the statement to a String.
(package private) void	trace(long startTimeNanos, long rowCount)	Print information about the statement executed if info trace level is enabled.
long	update()	Execute the statement.

Methods inherited from class java.lang.Object

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

Field Detail

session

protected SessionLocal session

The session.

sqlStatement

protected java.lang.String sqlStatement

The SQL string.

sqlTokens

protected java.util.ArrayList<Token> sqlTokens

The SQL tokens.

create

protected boolean create

Whether to create a new object (for indexes).

parameters

protected java.util.ArrayList<Parameter> parameters

The list of parameters.

prepareAlways

protected boolean prepareAlways

If the query should be prepared before each execution. This is set for queries with LIKE ?, because the query plan depends on the parameter value.

modificationMetaId

private long modificationMetaId

command

private Command command

persistedObjectId

private int persistedObjectId

Used to preserve object identities on database startup. 0 if object is not stored, -1 if object is stored and its ID is already read, >0 if object is stored and its id is not yet read.

currentRowNumber

private long currentRowNumber

rowScanCount

private int rowScanCount

cteCleanups

private java.util.List<TableView> cteCleanups

Common table expressions (CTE) in queries require us to create temporary views, which need to be cleaned up once a command is done executing.

Constructor Detail

Prepared

public Prepared(SessionLocal session)

Create a new object.

Parameters:

session - the session

Method Detail

isTransactional

public abstract boolean isTransactional()

Check if this command is transactional. If it is not, then it forces the current transaction to commit.

Returns:

true if it is

queryMeta

public abstract ResultInterface queryMeta()

Get an empty result set containing the meta data.

Returns:

the result set

getType

public abstract int getType()

Get the command type as defined in CommandInterface

Returns:

the statement type

isReadOnly

public boolean isReadOnly()

Check if this command is read only.

Returns:

true if it is

needRecompile

public boolean needRecompile()

Check if the statement needs to be re-compiled.

Returns:

true if it must

getModificationMetaId

long getModificationMetaId()

Get the meta data modification id of the database when this statement was compiled.

Returns:

the meta data modification id

setModificationMetaId

void setModificationMetaId(long id)

Set the meta data modification id of this statement.

Parameters:

id - the new id

setParameterList

public void setParameterList(java.util.ArrayList<Parameter> parameters)

Set the parameter list of this statement.

Parameters:

parameters - the parameter list

getParameters

public java.util.ArrayList<Parameter> getParameters()

Get the parameter list.

Returns:

the parameter list

checkParameters

protected void checkParameters()

Check if all parameters have been set.

Throws:

DbException - if any parameter has not been set

setCommand

public void setCommand(Command command)

Set the command.

Parameters:

command - the new command

isQuery

public boolean isQuery()

Check if this object is a query.

Returns:

true if it is

prepare

public void prepare()

Prepare this statement.

update

public long update()

Execute the statement.

Returns:

the update count

Throws:

DbException - if it is a query

query

public ResultInterface query(long maxrows)

Execute the query.

Parameters:

maxrows - the maximum number of rows to return

Returns:

the result set

Throws:

DbException - if it is not a query

setSQL

public final void setSQL(java.lang.String sql,
                         java.util.ArrayList<Token> sqlTokens)

Set the SQL statement.

Parameters:

sql - the SQL statement

sqlTokens - the SQL tokens

getSQL

public final java.lang.String getSQL()

Get the SQL statement.

Returns:

the SQL statement

getSQLTokens

public final java.util.ArrayList<Token> getSQLTokens()

Get the SQL tokens.

Returns:

the SQL tokens

getPersistedObjectId

public int getPersistedObjectId()

Get the object id to use for the database object that is created in this statement. This id is only set when the object is already persisted. If not set, this method returns 0.

Returns:

the object id or 0 if not set

getObjectId

protected int getObjectId()

Get the current object id, or get a new id from the database. The object id is used when creating new database object (CREATE statement). This method may be called only once.

Returns:

the object id

getPlanSQL

public java.lang.String getPlanSQL(int sqlFlags)

Get the SQL statement with the execution plan.

Parameters:

sqlFlags - formatting flags

Returns:

the execution plan

checkCanceled

public void checkCanceled()

Check if this statement was canceled.

Throws:

DbException - if it was canceled

setPersistedObjectId

public void setPersistedObjectId(int i)

Set the persisted object id for this statement.

Parameters:

i - the object id

setSession

public void setSession(SessionLocal currentSession)

Set the session for this statement.

Parameters:

currentSession - the new session

trace

void trace(long startTimeNanos,
           long rowCount)

Print information about the statement executed if info trace level is enabled.

Parameters:

startTimeNanos - when the statement was started

rowCount - the query or update row count

setPrepareAlways

public void setPrepareAlways(boolean prepareAlways)

Set the prepare always flag. If set, the statement is re-compiled whenever it is executed.

Parameters:

prepareAlways - the new value

setCurrentRowNumber

public void setCurrentRowNumber(long rowNumber)

Set the current row number.

Parameters:

rowNumber - the row number

getCurrentRowNumber

public long getCurrentRowNumber()

Get the current row number.

Returns:

the row number

setProgress

private void setProgress()

Notifies query progress via the DatabaseEventListener

toString

public java.lang.String toString()

Convert the statement to a String.

Overrides:

toString in class java.lang.Object

Returns:

the SQL statement

getSimpleSQL

public static java.lang.String getSimpleSQL(Expression[] list)

Get the SQL snippet of the expression list.

Parameters:

list - the expression list

Returns:

the SQL snippet

setRow

protected DbException setRow(DbException e,
                             long rowId,
                             java.lang.String values)

Set the SQL statement of the exception to the given row.

Parameters:

e - the exception

rowId - the row number

values - the values of the row

Returns:

the exception

isCacheable

public boolean isCacheable()

getCteCleanups

public java.util.List<TableView> getCteCleanups()

Returns:

the temporary views created for CTE's.

setCteCleanups

public void setCteCleanups(java.util.List<TableView> cteCleanups)

Set the temporary views created for CTE's.

Parameters:

cteCleanups - the temporary views

getSession

public final SessionLocal getSession()

collectDependencies

public void collectDependencies(java.util.HashSet<DbObject> dependencies)

Find and collect all DbObjects, this Prepared depends on.

Parameters:

dependencies - collection of dependencies to populate