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Interface java.sql.Statement
- public interface Statement
A Statement object is used for executing a static SQL statement
and obtaining the results produced by it.
Only one ResultSet per Statement can be open at any point in
time. Therefore, if the reading of one ResultSet is interleaved
with the reading of another, each must have been generated by
different Statements. All statement execute methods implicitly
close a statment's current ResultSet if an open one exists.
- See Also:
- createStatement, ResultSet
-
cancel()
- Cancel can be used by one thread to cancel a statement that
is being executed by another thread.
-
clearWarnings()
- After this call, getWarnings returns null until a new warning is
reported for this Statement.
-
close()
- In many cases, it is desirable to immediately release a
Statements's database and JDBC resources instead of waiting for
this to happen when it is automatically closed; the close
method provides this immediate release.
-
execute(String)
- Execute a SQL statement that may return multiple results.
-
executeQuery(String)
- Execute a SQL statement that returns a single ResultSet.
-
executeUpdate(String)
- Execute a SQL INSERT, UPDATE or DELETE statement.
-
getMaxFieldSize()
- The maxFieldSize limit (in bytes) is the maximum amount of data
returned for any column value; it only applies to BINARY,
VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR
columns.
-
getMaxRows()
- The maxRows limit is the maximum number of rows that a
ResultSet can contain.
-
getMoreResults()
- getMoreResults moves to a Statement's next result.
-
getQueryTimeout()
- The queryTimeout limit is the number of seconds the driver will
wait for a Statement to execute.
-
getResultSet()
- getResultSet returns the current result as a ResultSet.
-
getUpdateCount()
- getUpdateCount returns the current result as an update count;
if the result is a ResultSet or there are no more results, -1
is returned.
-
getWarnings()
- The first warning reported by calls on this Statement is
returned.
-
setCursorName(String)
- setCursorname defines the SQL cursor name that will be used by
subsequent Statement execute methods.
-
setEscapeProcessing(boolean)
- If escape scanning is on (the default), the driver will do
escape substitution before sending the SQL to the database.
-
setMaxFieldSize(int)
- The maxFieldSize limit (in bytes) is set to limit the size of
data that can be returned for any column value; it only applies
to BINARY, VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and
LONGVARCHAR fields.
-
setMaxRows(int)
- The maxRows limit is set to limit the number of rows that any
ResultSet can contain.
-
setQueryTimeout(int)
- The queryTimeout limit is the number of seconds the driver will
wait for a Statement to execute.
executeQuery
public abstract ResultSet executeQuery(String sql) throws SQLException
- Execute a SQL statement that returns a single ResultSet.
- Parameters:
- sql - typically this is a static SQL SELECT statement
- Returns:
- a ResultSet that contains the data produced by the
query; never null
- Throws: SQLException
- if a database-access error occurs.
executeUpdate
public abstract int executeUpdate(String sql) throws SQLException
- Execute a SQL INSERT, UPDATE or DELETE statement. In addition,
SQL statements that return nothing such as SQL DDL statements
can be executed.
- Parameters:
- sql - a SQL INSERT, UPDATE or DELETE statement or a SQL
statement that returns nothing
- Returns:
- either the row count for INSERT, UPDATE or DELETE or 0
for SQL statements that return nothing
- Throws: SQLException
- if a database-access error occurs.
close
public abstract void close() throws SQLException
- In many cases, it is desirable to immediately release a
Statements's database and JDBC resources instead of waiting for
this to happen when it is automatically closed; the close
method provides this immediate release.
Note: A Statement is automatically closed when it is
garbage collected. When a Statement is closed, its current
ResultSet, if one exists, is also closed.
- Throws: SQLException
- if a database-access error occurs.
getMaxFieldSize
public abstract int getMaxFieldSize() throws SQLException
- The maxFieldSize limit (in bytes) is the maximum amount of data
returned for any column value; it only applies to BINARY,
VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR
columns. If the limit is exceeded, the excess data is silently
discarded.
- Returns:
- the current max column size limit; zero means unlimited
- Throws: SQLException
- if a database-access error occurs.
setMaxFieldSize
public abstract void setMaxFieldSize(int max) throws SQLException
- The maxFieldSize limit (in bytes) is set to limit the size of
data that can be returned for any column value; it only applies
to BINARY, VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and
LONGVARCHAR fields. If the limit is exceeded, the excess data
is silently discarded. For maximum portability use values
greater than 256.
- Parameters:
- max - the new max column size limit; zero means unlimited
- Throws: SQLException
- if a database-access error occurs.
getMaxRows
public abstract int getMaxRows() throws SQLException
- The maxRows limit is the maximum number of rows that a
ResultSet can contain. If the limit is exceeded, the excess
rows are silently dropped.
- Returns:
- the current max row limit; zero means unlimited
- Throws: SQLException
- if a database-access error occurs.
setMaxRows
public abstract void setMaxRows(int max) throws SQLException
- The maxRows limit is set to limit the number of rows that any
ResultSet can contain. If the limit is exceeded, the excess
rows are silently dropped.
- Parameters:
- max - the new max rows limit; zero means unlimited
- Throws: SQLException
- if a database-access error occurs.
setEscapeProcessing
public abstract void setEscapeProcessing(boolean enable) throws SQLException
- If escape scanning is on (the default), the driver will do
escape substitution before sending the SQL to the database.
Note: Since prepared statements have usually been parsed prior
to making this call, disabling escape processing for prepared
statements will like have no affect.
- Parameters:
- enable - true to enable; false to disable
- Throws: SQLException
- if a database-access error occurs.
getQueryTimeout
public abstract int getQueryTimeout() throws SQLException
- The queryTimeout limit is the number of seconds the driver will
wait for a Statement to execute. If the limit is exceeded, a
SQLException is thrown.
- Returns:
- the current query timeout limit in seconds; zero means unlimited
- Throws: SQLException
- if a database-access error occurs.
setQueryTimeout
public abstract void setQueryTimeout(int seconds) throws SQLException
- The queryTimeout limit is the number of seconds the driver will
wait for a Statement to execute. If the limit is exceeded, a
SQLException is thrown.
- Parameters:
- seconds - the new query timeout limit in seconds; zero means unlimited
- Throws: SQLException
- if a database-access error occurs.
cancel
public abstract void cancel() throws SQLException
- Cancel can be used by one thread to cancel a statement that
is being executed by another thread.
- Throws: SQLException
- if a database-access error occurs.
getWarnings
public abstract SQLWarning getWarnings() throws SQLException
- The first warning reported by calls on this Statement is
returned. A Statment's execute methods clear its SQLWarning
chain. Subsequent Statement warnings will be chained to this
SQLWarning.
The warning chain is automatically cleared each time
a statement is (re)executed.
Note: If you are processing a ResultSet then any
warnings associated with ResultSet reads will be chained on the
ResultSet object.
- Returns:
- the first SQLWarning or null
- Throws: SQLException
- if a database-access error occurs.
clearWarnings
public abstract void clearWarnings() throws SQLException
- After this call, getWarnings returns null until a new warning is
reported for this Statement.
- Throws: SQLException
- if a database-access error occurs.
setCursorName
public abstract void setCursorName(String name) throws SQLException
- setCursorname defines the SQL cursor name that will be used by
subsequent Statement execute methods. This name can then be
used in SQL positioned update/delete statements to identify the
current row in the ResultSet generated by this statement. If
the database doesn't support positioned update/delete, this
method is a noop.
Note: By definition, positioned update/delete
execution must be done by a different Statement than the one
which generated the ResultSet being used for positioning. Also,
cursor names must be unique within a Connection.
- Parameters:
- name - the new cursor name.
- Throws: SQLException
- if a database-access error occurs.
execute
public abstract boolean execute(String sql) throws SQLException
- Execute a SQL statement that may return multiple results.
Under some (uncommon) situations a single SQL statement may return
multiple result sets and/or update counts. Normally you can ignore
this, unless you're executing a stored procedure that you know may
return multiple results, or unless you're dynamically executing an
unknown SQL string. The "execute", "getMoreResults", "getResultSet"
and "getUpdateCount" methods let you navigate through multiple results.
The "execute" method executes a SQL statement and indicates the
form of the first result. You can then use getResultSet or
getUpdateCount to retrieve the result, and getMoreResults to
move to any subsequent result(s).
- Parameters:
- sql - any SQL statement
- Returns:
- true if the next result is a ResultSet; false if it is
an update count or there are no more results
- Throws: SQLException
- if a database-access error occurs.
- See Also:
- getResultSet, getUpdateCount, getMoreResults
getResultSet
public abstract ResultSet getResultSet() throws SQLException
- getResultSet returns the current result as a ResultSet. It
should only be called once per result.
- Returns:
- the current result as a ResultSet; null if the result
is an update count or there are no more results
- Throws: SQLException
- if a database-access error occurs.
- See Also:
- execute
getUpdateCount
public abstract int getUpdateCount() throws SQLException
- getUpdateCount returns the current result as an update count;
if the result is a ResultSet or there are no more results, -1
is returned. It should only be called once per result.
- Returns:
- the current result as an update count; -1 if it is a
ResultSet or there are no more results
- Throws: SQLException
- if a database-access error occurs.
- See Also:
- execute
getMoreResults
public abstract boolean getMoreResults() throws SQLException
- getMoreResults moves to a Statement's next result. It returns true if
this result is a ResultSet. getMoreResults also implicitly
closes any current ResultSet obtained with getResultSet.
There are no more results when (!getMoreResults() &&
(getUpdateCount() == -1)
- Returns:
- true if the next result is a ResultSet; false if it is
an update count or there are no more results
- Throws: SQLException
- if a database-access error occurs.
- See Also:
- execute
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