Qore::SQL::SQLStatement Class Reference

The SQLStatement class provides the most flexibilty for executing SQL on a database server. More...

Inheritance diagram for Qore::SQL::SQLStatement:
[legend]

## Public Member Functions

bool | active ()
| Returns True if the object is currently active and has a connection or transaction lock allocated to it, or False if not. More...
int | affectedRows ()
| Returns the number of rows affected by the last call to SQLStatement::exec() More...
nothing | beginTransaction ()
| Manually starts a transaction and allocates a connection or grabs the transaction lock according to the object used in the SQLStatement::constructor() More...
nothing | bind (...)
| Binds placeholder buffer specifications and values to buffers defined in SQLStatement::prepare() More...
nothing | bindArgs (softlist vargs)
| Binds placeholder buffer specifications and values given as a list in the single argument to the method to buffers defined in SQLStatement::prepare() More...
nothing | bindPlaceholders (...)
| Binds placeholder buffer specifications to buffers defined in SQLStatement::prepare() More...
nothing | bindPlaceholdersArgs (softlist vargs)
| Binds placeholder buffer specifications given as a list in the single argument to the method to buffers defined in SQLStatement::prepare() More...
nothing | bindValues (...)
| Binds values to value buffer specifications to buffers defined in SQLStatement::prepare() More...
nothing | bindValuesArgs (softlist vargs)
| Binds values to value buffer specifications given as a list in the single argument to the method to value buffers defined in SQLStatement::prepare() More...
nothing | close ()
| Closes the statement if it is open, however this method does not release the connection or transaction lock. More...
nothing | commit ()
| Commits the transaction, releases the connection or the transaction lock according to the object used in the SQLStatement::constructor(), and closes the SQLStatement. More...
| constructor (Datasource ds)
| Creates the SQLStatement object based on the given Datasource object that provides the connection to the database. More...
| constructor (DatasourcePool dsp)
| Creates the SQLStatement object based on the given DatasourcePool object that provides the connection to the database. More...
| copy ()
| Throws an exception; objects of this class cannot be copied. More...
bool | currentThreadInTransaction ()
| Returns True if the current thread is in a transaction (i.e. holds the transaction lock), False if not. More...
nothing | define ()
| Performs an explicit define operation on the SQLStatement. More...
hash | describe ()
| Describes columns in the statement result. More...
| destructor ()
| Closes the statement if it is open and destroys the object. More...
nothing | exec (...)
| Executes the bound statement with any bound buffers, also optionally allows binding placeholder buffer specifications and values to buffers defined in SQLStatement::prepare() before executing the statement. More...
nothing | execArgs (softlist vargs)
| Executes the bound statement with any bound buffers, also optionally allows binding placeholder buffer specifications and values given as a list in the single argument to the method to buffers defined in SQLStatement::prepare() More...
hash | fetchColumns (softint rows=-1)
| Retrieves a block of rows as a hash of lists with the maximum number of rows determined by the argument passed; automatically advances the row pointer; with this call it is not necessary to call SQLStatement::next(). More...
*hash | fetchRow ()
| Retrieves the current row as a hash where the keys are the column names and the values are the column values. More...
list | fetchRows (softint rows=-1)
| Retrieves a block of rows as a list of hashes with the maximum number of rows determined by the argument passed; automatically advances the row pointer; with this call it is not necessary to call SQLStatement::next() More...
hash | getOutput ()
| Retrieves output buffers as a hash; result sets will be returned as hashes of lists. More...
hash | getOutputRows ()
| Retrieves output buffers as a hash; result sets will be returned as lists of hashes. More...
*string | getSQL ()
| Returns the current SQL string set with the call to SQLStatement::prepare() or SQLStatement::prepareRaw() or NOTHING if no SQL has been set. More...
*hash | getValue ()
| Retrieves the current row as a hash where the keys are the column names and the values are the column values. More...
auto | memberGate (string key)
| This method allows SQLStatement objects to be dereferenced directly as a hash for the current row being iterated, as memberGate methods are called implicitly when an unknown member is accessed from outside the class. More...
bool | next ()
| Increments the row pointer when retrieving rows from a select statement; returns True if there is a row to retrieve, False if not. More...
nothing | prepare (string sql,...)
| Saves an SQL statement that will be prepared and executed later, along with optional arguments. More...
nothing | prepareRaw (string sql)
| Saves an SQL statement that will be prepared and executed later. More...
nothing | rollback ()
| Closes the SQLStatement, performs a transaction rollback, and releases the connection or the transaction lock according to the object used in the SQLStatement::constructor(), and closes the SQLStatement. More...
bool | valid ()
| returns True if the object is currently pointing at a valid element, False if not (use when iterating with SQLStatement::next()) More...

## Detailed Description

The SQLStatement class provides the most flexibilty for executing SQL on a database server.

Restrictions:
  Qore::PO_NO_DATABASE

This class allows statements to be executed and result sets to be iteratively returned in all formats supported by Qore (single row at a time as a hash or blocks of rows as either hashes of lists or lists of hashes). The same flexibility of choosing the output format for result sets also applies to output values from stored procedure or function execution, for example.

This class does not differentiate between executing select statements, stored procedures, functions, or other SQL code; the transaction lock for Datasource objects and a dedicated connection for DatasourcePool objects is allocated to the object when the connection is necessary, and it is not automatically released by this class. The transaction lock or connection must be manually released by calling SQLStatement::commit() or SQLStatement::rollback() (or the methods with the same name in the parent Datasource or DatasourcePool object).

Here is an example executing a select statement:

{
SQLStatement stmt(ds);
# release transaction lock on exit
on_exit stmt.commit();
stmt.prepare("select * from table");
while (stmt.next()) {
hash row = stmt.fetchRow();
do_something(row);
}
}

Note
  - Most commands are executed implicitly; for example, in the example above there is no call to SQLStatement::exec() as it is executed implicitly in the initial call to SQLStatement::next().
  - Current column values in query results iterated with SQLStatement::next() as above can also be dereferenced directly from the SQLStatement object by using the column name in lower case as a member name (using SQLStatement::memberGate(), see that method for an example)
  - Query results can also be returned in blocks using SQLStatement::fetchRows() and SQLStatement::fetchColumns() ("rows" and "columns" in this case refer to the output data format; also using these methods there is no need to call SQLStatement::next())
  - When using an SQLStatement object with a DatasourcePool, the statement will be automatically closed when the connection is returned to the pool (for example, by committing or rolling back the transaction).

The following methods are useful when executing all statements:

- SQLStatement::prepare()
- SQLStatement::prepareRaw()
- SQLStatement::bind()
- SQLStatement::bindArgs()
- SQLStatement::bindPlaceholders()
- SQLStatement::bindPlaceholdersArgs()
- SQLStatement::bindValues()
- SQLStatement::bindValuesArgs()
- SQLStatement::exec()
- SQLStatement::execArgs()
- SQLStatement::beginTransaction()
- SQLStatement::commit()
- SQLStatement::rollback()
- SQLStatement::close()
- SQLStatement::getSQL()
- SQLStatement::active()

The following methods are useful when executing select statements:

- SQLStatement::next()
- SQLStatement::fetchRow()
- SQLStatement::fetchRows()
- SQLStatement::fetchColumns()

The following methods are useful when executing stored procedures, functions, or other non-select SQL statements:

- SQLStatement::getOutput()
- SQLStatement::getOutputRows()

Note
  This class is not available with the PO_NO_DATABASE parse option

## Member Function Documentation

## active()

bool Qore::SQL::SQLStatement::active | ( |  | ) |

Returns True if the object is currently active and has a connection or transaction lock allocated to it, or False if not.

Returns
  True if the object is currently active and has a connection or transaction lock allocated to it, or False if not

Code Flags:
  CONSTANT

Example:
  if (stmt.active())
  stmt.commit();

## affectedRows()

int Qore::SQL::SQLStatement::affectedRows | ( |  | ) |

Returns the number of rows affected by the last call to SQLStatement::exec()

Returns
  the number of rows affected by the last call to SQLStatement::exec()

Example:
  int rc = stmt.affectedRows();

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed; see the relevant DBI driver docs for more information

## beginTransaction()

nothing Qore::SQL::SQLStatement::beginTransaction | ( |  | ) |

Manually starts a transaction and allocates a connection or grabs the transaction lock according to the object used in the SQLStatement::constructor()

Example:
  stmt.beginTransaction();

## bind()

nothing Qore::SQL::SQLStatement::bind | ( |  | ... | ) |

Binds placeholder buffer specifications and values to buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method.

Any arguments previously bound will be released when this call is made.

Note
  You can also bind directly when calling SQLStatement::exec() or SQLStatement::execArgs() as a shortcut as well, in which case it's not necessary to make an extra call to this method.

Parameters

  ... | Arguments to placeholder specifications (if required by the underlying DBI driver) and bind by value arguments

Example:
  stmt.prepare("insert into table (id, name) values (%v, %v)");
  foreach hash h in (l) {
  stmt.bind(h.id, h.name);
  stmt.exec();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications; see the relevant DBI driver docs for more information

See also
  SQLStatement::bindArgs(), SQLStatement::bindPlaceholders(), SQLStatement::bindPlaceholdersArgs(), SQLStatement::bindValues(), and SQLStatement::bindValuesArgs()

## bindArgs()

nothing Qore::SQL::SQLStatement::bindArgs | ( | softlist | vargs | ) |

Binds placeholder buffer specifications and values given as a list in the single argument to the method to buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method.

Any arguments previously bound will be released when this call is made.

Note
  You can also bind directly when calling SQLStatement::exec() or SQLStatement::execArgs() as a shortcut as well, in which case it's not necessary to make an extra call to this method.

Parameters

  vargs | Arguments to placeholder specifications (if required by the underlying DBI driver) and bind by value arguments

Example:
  stmt.prepare("insert into table (id, name) values (%v, %v)");
  foreach hash h in (l) {
  list args = (h.id, h.name);
  stmt.bindArgs(args);
  stmt.exec();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications; see the relevant DBI driver docs for more information

See also
  SQLStatement::bind(), SQLStatement::bindPlaceholders(), SQLStatement::bindPlaceholdersArgs(), SQLStatement::bindValues(), and SQLStatement::bindValuesArgs()

## bindPlaceholders()

nothing Qore::SQL::SQLStatement::bindPlaceholders | ( |  | ... | ) |

Binds placeholder buffer specifications to buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method. Only placeholder buffer specifications will be processed; value buffer specifications will be skipped by this method.

Any buffer specifications previously defined will be released when this call is made.

Note
  You can also bind buffer specifications directly when calling SQLStatement::exec() or SQLStatement::execArgs() as a shortcut as well, in which case it's not necessary to make an extra call to this method.
  Not all DBI drivers require binding placeholders specification.

Parameters

  ... | Arguments to placeholder specifications (if required by the underlying DBI driver)

Example:
  stmt.prepare("begin select sysdate into :sd from dual", Type::Date); end;
  stmt.bindPlaceholders(Type::Date);
  date d = stmt.getOutput().sd;

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications; see the relevant DBI driver docs for more information

See also
  SQLStatement::bind(), SQLStatement::bindArgs(), SQLStatement::bindPlaceholdersArgs(), SQLStatement::bindValues(), and SQLStatement::bindValuesArgs()

## bindPlaceholdersArgs()

nothing Qore::SQL::SQLStatement::bindPlaceholdersArgs | ( | softlist | vargs | ) |

Binds placeholder buffer specifications given as a list in the single argument to the method to buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method. Only placeholder buffer specifications will be processed; value buffer specifications will be skipped by this method.

Any buffer specifications previously defined will be released when this call is made.

Note
  You can also bind buffer specifications directly when calling SQLStatement::exec() or SQLStatement::execArgs() as a shortcut as well, in which case it's not necessary to make an extra call to this method.
  Not all DBI drivers require binding placeholders specification.

Parameters

  vargs | Arguments to placeholder specifications (if required by the underlying DBI driver)

Example:
  stmt.prepare("begin select sysdate into :sd from dual", Type::Date); end;
  list l = list(Type::Date);
  stmt.bindPlaceholdersArgs(l);
  date d = stmt.getOutput().sd;

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications; see the relevant DBI driver docs for more information

See also
  SQLStatement::bind(), SQLStatement::bindArgs(), SQLStatement::bindPlaceholders(), SQLStatement::bindValues(), and SQLStatement::bindValuesArgs()

## bindValues()

nothing Qore::SQL::SQLStatement::bindValues | ( |  | ... | ) |

Binds values to value buffer specifications to buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method.

Any values previously bound will be released when this call is made.

Note
  You can also bind directly when calling SQLStatement::exec() or SQLStatement::execArgs() as a shortcut as well, in which case it's not necessary to make an extra call to this method.

Parameters

  ... | Arguments to bind by value arguments

Example:
  stmt.prepare("insert into table (id, name) values (%v, %v)");
  foreach hash h in (l) {
  stmt.bindValues(h.id, h.name);
  stmt.exec();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications; see the relevant DBI driver docs for more information

See also
  SQLStatement::bind(), SQLStatement::bindArgs(), SQLStatement::bindPlaceholders(), SQLStatement::bindPlaceholdersArgs(), and SQLStatement::bindValuesArgs().

## bindValuesArgs()

nothing Qore::SQL::SQLStatement::bindValuesArgs | ( | softlist | vargs | ) |

Binds values to value buffer specifications given as a list in the single argument to the method to value buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method.

Any values previously bound will be released when this call is made.

Note
  You can also bind directly when calling SQLStatement::exec() or SQLStatement::execArgs() as a shortcut as well, in which case it's not necessary to make an extra call to this method.

Parameters

  vargs | Arguments to bind by value arguments

Example:
  stmt.prepare("insert into table (id, name) values (%v, %v)");
  foreach hash h in (l) {
  list args = (h.id, h.name);
  stmt.bindValuesArgs(args);
  stmt.exec();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications; see the relevant DBI driver docs for more information

## close()

nothing Qore::SQL::SQLStatement::close | ( |  | ) |

Closes the statement if it is open, however this method does not release the connection or transaction lock.

Example:
  stmt.close();

## commit()

nothing Qore::SQL::SQLStatement::commit | ( |  | ) |

Commits the transaction, releases the connection or the transaction lock according to the object used in the SQLStatement::constructor(), and closes the SQLStatement.

Example:
  stmt.commit();

Note
  For possible exceptions; see DBI driver docs for the commit() method

## constructor() [1/2]

Qore::SQL::SQLStatement::constructor | ( | Datasource | ds | ) |

Creates the SQLStatement object based on the given Datasource object that provides the connection to the database.

This method will throw an exception only if the object passed as an argument uses a driver that does not support the prepared statement interface added in Qore version 0.8.1.

Parameters

  ds | The Datasource object to use for the DB connection for the SQLStatement object

Example:
  SQLStatement stmt(db);

Exceptions

  SQLSTATEMENT-ERROR | the DBI driver for the given object does not support the prepared statement API

Since
  Qore 0.8.1

## constructor() [2/2]

Qore::SQL::SQLStatement::constructor | ( | DatasourcePool | dsp | ) |

Creates the SQLStatement object based on the given DatasourcePool object that provides the connection to the database.

This method will throw an exception only if the object passed as an argument uses a driver that does not support the prepared statement interface added in Qore version 0.8.1.

Parameters

  dsp | The DatasourcePool object to use for the DB connection for the SQLStatement object

Example:
  SQLStatement stmt(db);

Exceptions

  SQLSTATEMENT-ERROR | the DBI driver for the given object does not support the prepared statement API

Since
  Qore 0.8.1

## copy()

Qore::SQL::SQLStatement::copy | ( |  | ) |

Throws an exception; objects of this class cannot be copied.

Exceptions

  SQLSTATEMENT-COPY-ERROR | SQLStatement objects cannot be copied

## currentThreadInTransaction()

bool Qore::SQL::SQLStatement::currentThreadInTransaction | ( |  | ) |

Returns True if the current thread is in a transaction (i.e. holds the transaction lock), False if not.

Returns
  True if the current thread is in a transaction (i.e. holds the transaction lock), False if not

Code Flags:
  CONSTANT

Example:
  bool b = stmt.currentThreadInTransaction();

Since
  Qore 0.8.12

## define()

nothing Qore::SQL::SQLStatement::define | ( |  | ) |

Performs an explicit define operation on the SQLStatement.

It is not encessary to call this method manually; define operations are implicitly executed when needed when retrieving values from a select statement

Example:
  {
  SQLStatement stmt(ds);
  # release transaction lock on exit
  on_exit stmt.commit();
  stmt.prepare("select * from table");
  stmt.exec();
  stmt.define();
  # note that the SQLStatement::next() would implicitly execute exec() and define()
  while (stmt.next()) {
  hash row = stmt.fetchRow();
  do_something(row);
  }
  }

## describe()

hash Qore::SQL::SQLStatement::describe | ( |  | ) |

Describes columns in the statement result.

Returns
  a hash with (column_name: description_hash) format, where each description_hash has the following keys:
  - `"name"`: (string) the column name
  - `"type"`: (integer) the column type code (as returned by <value>::typeCode())
  - `"maxsize"`: (integer) the maximum size of the column
  - `"native_type"`: (string) the database-specific name of the type
  - `"internal_id"`: (integer) the database-specific type code of the type

## destructor()

Qore::SQL::SQLStatement::destructor | ( |  | ) |

Closes the statement if it is open and destroys the object.

Example:
  delete stmt;

## exec()

nothing Qore::SQL::SQLStatement::exec | ( |  | ... | ) |

Executes the bound statement with any bound buffers, also optionally allows binding placeholder buffer specifications and values to buffers defined in SQLStatement::prepare() before executing the statement.

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Optional arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method.

If bind arguments are provided, any arguments previously bound will be released when this call is made.

After calling this method to execute the statement, to retrieve information about the call or output values bound in the call, call SQLStatement::affectedRows(), SQLStatement::getOutput(), or SQLStatement::getOutputRows() as needed.

To retrieve rows from a select statement call either SQLStatement::next() and SQLStatement::fetchRow(), or SQLStatement::fetchRows() or SQLStatement::fetchColumns() as needed.

Parameters

  ... | Optional arguments to placeholder specifications (if required by the underlying DBI driver) and bind by value arguments can be given in the call to the method; if present, arguments are bound before the statement is executed

Example:
  stmt.prepare("insert into table (id, name) values (%v, %v)");
  foreach hash h in (l) {
  stmt.exec(h.id, h.name);
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare(); the SQLStatement uses a DatasourcePool an the statement was prepared on another connection

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed; see the relevant DBI driver docs for more information

See also
  SQLStatement::execArgs()

## execArgs()

nothing Qore::SQL::SQLStatement::execArgs | ( | softlist | vargs | ) |

Executes the bound statement with any bound buffers, also optionally allows binding placeholder buffer specifications and values given as a list in the single argument to the method to buffers defined in SQLStatement::prepare()

If the statement has not previously been prepared with the DB API, it will be implicitly prepared by this method call. This means that this call will cause a connection to be dedicated from a DatasourcePool object or the transaction lock to be grabbed with a Datasource object, depending on the argument to SQLStatement::constructor().

Optional arguments to buffer specifications must be given in the same order as declared in the string given to the SQLStatement::prepare() method.

If bind arguments are provided, any arguments previously bound will be released when this call is made.

After calling this method to execute the statement, to retrieve information about the call or output values bound in the call, call SQLStatement::affectedRows(), SQLStatement::getOutput(), or SQLStatement::getOutputRows() as needed.

To retrieve rows from a select statement call either SQLStatement::next() and SQLStatement::fetchRow(), or SQLStatement::fetchRows() or SQLStatement::fetchColumns() as needed.

Parameters

  vargs | Optional arguments to placeholder specifications (if required by the underlying DBI driver) and bind by value arguments can be given in the call to the method; if present, arguments are bound before the statement is executed

Example:
  stmt.prepare("insert into table (id, name) values (%v, %v)");
  foreach hash h in (l) {
  list args = (h.id, h.name);
  stmt.execArgs(args);
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw(); the SQLStatement uses a DatasourcePool an the statement was prepared on another connection

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed; see the relevant DBI driver docs for more information

See also
  SQLStatement::exec()

## fetchColumns()

hash Qore::SQL::SQLStatement::fetchColumns | ( | softint | rows = `-1` | ) |

Retrieves a block of rows as a hash of lists with the maximum number of rows determined by the argument passed; automatically advances the row pointer; with this call it is not necessary to call SQLStatement::next().

If the argument passed is omitted or less than or equal to zero, then all available rows from the current row position are retrieved, also if fewer rows are available than requested then only the rows available are retrieved.

Parameters

  rows | The maximum number of rows to retrieve, if this argument is omitted, negative, or equal to zero, then all available rows from the current row position are retrieved

Returns
  a hash (giving column names) of lists (giving row values for each column) of data returned; each list will have at most rows elements (unless rows is negative, in which case all available rows are returned). If the total number of rows available is less than rows (if rows is positive), then the last data returned by this method may return short lists. If no more rows are available, then an empty hash is returned

Example:
  hash h = stmt.fetchColumns(-1);

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  - There is no need to call SQLStatement::next() when calling this method; the method automatically iterates through the given number of rows
  - Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed or when row values are retrieved; see the relevant DBI driver docs for more information

## fetchRow()

*hash Qore::SQL::SQLStatement::fetchRow | ( |  | ) |

Retrieves the current row as a hash where the keys are the column names and the values are the column values.

Use with SQLStatement::next() to iterate through the results of a select statement one row at a time

Returns
  the current row as a hash where the keys are the column names and the values are the column values

Example:
  while (stmt.next()) {
  hash h = stmt.fetchRow();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed or when row values are retrieved; see the relevant DBI driver docs for more information

## fetchRows()

list Qore::SQL::SQLStatement::fetchRows | ( | softint | rows = `-1` | ) |

Retrieves a block of rows as a list of hashes with the maximum number of rows determined by the argument passed; automatically advances the row pointer; with this call it is not necessary to call SQLStatement::next()

If the argument passed is omitted or less than or equal to zero, then all available rows from the current row position are retrieved, also if fewer rows are available than requested then only the rows available are retrieved.

If no more rows are available then an empty list is returned.

Parameters

  rows | The maximum number of rows to retrieve, if this argument is omitted, negative, or equal to zero, then all available rows from the current row position are retrieved

Example:
  list l = stmt.fetchRows(-1);

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  - There is no need to call SQLStatement::next() when calling this method; the method automatically iterates through the given number of rows
  - Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed or when row values are retrieved; see the relevant DBI driver docs for more information

## getOutput()

hash Qore::SQL::SQLStatement::getOutput | ( |  | ) |

Retrieves output buffers as a hash; result sets will be returned as hashes of lists.

Returns
  Returns a hash of output buffers; result sets will be returned as hashes of lists. Each key in the hash is the same as the name given to the placeholder specification in the call to SQLStatement::prepare() or SQLStatement::prepareRaw()

Example:
  hash h = stmt.getOutput();

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed or when output values are retrieved; see the relevant DBI driver docs for more information

## getOutputRows()

hash Qore::SQL::SQLStatement::getOutputRows | ( |  | ) |

Retrieves output buffers as a hash; result sets will be returned as lists of hashes.

Returns
  Retrieves output buffers as a hash; result sets will be returned as lists of hashes. Each key in the hash is the same as the name given to the placeholder specification in the call to SQLStatement::prepare() or SQLStatement::prepareRaw()

Example:
  hash h = stmt.getOutputRows();

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed or when output values are retrieved; see the relevant DBI driver docs for more information

## getSQL()

*string Qore::SQL::SQLStatement::getSQL | ( |  | ) |

Returns the current SQL string set with the call to SQLStatement::prepare() or SQLStatement::prepareRaw() or NOTHING if no SQL has been set.

Returns
  Returns the current SQL string set with the call to SQLStatement::prepare() or SQLStatement::prepareRaw() or NOTHING if no SQL has been set

Example:
  *string sql = stmt.getSQL();

## getValue()

*hash Qore::SQL::SQLStatement::getValue | ( |  | ) |

virtual

Retrieves the current row as a hash where the keys are the column names and the values are the column values.

Use with SQLStatement::next() to iterate through the results of a select statement one row at a time

Returns
  the current row as a hash where the keys are the column names and the values are the column values

Example:
  while (stmt.next()) {
  hash h = stmt.getValue();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  - Equivalent to SQLStatement::fetchRow()
  - Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed or when row values are retrieved; see the relevant DBI driver docs for more information

Since
  Qore 0.8.5

Implements Qore::AbstractIterator.

## memberGate()

auto Qore::SQL::SQLStatement::memberGate | ( | string | key | ) |

This method allows SQLStatement objects to be dereferenced directly as a hash for the current row being iterated, as memberGate methods are called implicitly when an unknown member is accessed from outside the class.

Code Flags:
  RET_VALUE_ONLY

Parameters

  key | the column name for the value to retrieve

Returns
  the current column value of the given row

Example:
  SQLStatement stmt(ds);
  # release transaction lock on exit
  on_exit stmt.commit();
  stmt.prepare("select name, birthdate from table");
  while (stmt.next()) {
  printf("name: %s birthdate: %y", stmt.name, stmt.birthdate);
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()
  SQLSTATEMENT-ITERATION-ERROR | Cannot dereference statement iteration context; make sure and call SQLStatement::next() before trying to dereference the current row being iterated
  ENCODING-CONVERSION-ERROR | this error is thrown if the given key cannot be converted to the default character encoding
  SQLSTATEMENT-COLUMN-ERROR | The given column name does not exist in the current row data

Note
  Column values can only be dereferenced using the automatic SQLStatement::memberGate() method while iterating a result set with SQLStatement::next(); the hash that will be dereferenced is equivalent to that returned by SQLStatement::fetchRow()

Since
  Qore 0.8.6

## next()

bool Qore::SQL::SQLStatement::next | ( |  | ) |

virtual

Increments the row pointer when retrieving rows from a select statement; returns True if there is a row to retrieve, False if not.

If this method returns True, then call SQLStatement::fetchRow() afterwards to retrieve the row

Returns
  True if there is a row to retrieve, False if not (no more rows to be retrieved)

Example:
  while (stmt.next()) {
  hash h = stmt.fetchRow();
  }

Exceptions

  SQLSTATEMENT-ERROR | No SQL has been set with SQLStatement::prepare() or SQLStatement::prepareRaw()

Note
  Exceptions could be thrown by the DBI driver when the statement is prepared or when attempting to bind the given arguments to buffer specifications or when the statement is executed; see the relevant DBI driver docs for more information

Implements Qore::AbstractIterator.

## prepare()

nothing Qore::SQL::SQLStatement::prepare | ( | string | sql,
|  |  | ...
| ) |  |

Saves an SQL statement that will be prepared and executed later, along with optional arguments.

The statement is actually only prepared when used for the first time, this is so that SQLStatement objects created with DatasourcePool objects use the DatasourcePool more efficiently, as many drivers require the actual DB API prepare call to be made on the same connection as the connection the statement will be executed on as well.

Note
  This method parses the SQL string for placeholders and bind by value tokens (`%v`); for a version of this method that does not parse the SQL string for placeholders and bind by value tokens, see SQLStatement::prepareRaw().

Parameters

  sql | The SQL string to prepare for execution on the DB server

Example:
  stmt.prepare("select * from table where id = %v");

## prepareRaw()

nothing Qore::SQL::SQLStatement::prepareRaw | ( | string | sql | ) |

Saves an SQL statement that will be prepared and executed later.

The statement is actually only prepared when used for the first time, this is so that SQLStatement objects created with DatasourcePool objects use the DatasourcePool more efficiently, as many drivers require the actual DB API prepare call to be made on the same connection as the connection the statement will be executed on as well.

Note
  This method does not parse the SQL string for placeholders and bind by value tokens (`%v`); for a version of this method that does parse the SQL string for placeholders and bind by value tokens, see SQLStatement::prepare().

Parameters

  sql | The SQL string to prepare for execution on the DB server

Example:
  stmt.prepareRaw("select * from table");

## rollback()

nothing Qore::SQL::SQLStatement::rollback | ( |  | ) |

Closes the SQLStatement, performs a transaction rollback, and releases the connection or the transaction lock according to the object used in the SQLStatement::constructor(), and closes the SQLStatement.

Example:
  stmt.rollback();

Note
  For possible exceptions; see DBI driver docs for the rollback() method

## valid()

bool Qore::SQL::SQLStatement::valid | ( |  | ) |

virtual

returns True if the object is currently pointing at a valid element, False if not (use when iterating with SQLStatement::next())

Returns
  True if the object is currently pointing at a valid element, False if not

Code Flags:
  CONSTANT

Example:
  if (i.valid())
  printf("current value: %y\n", i.getValue());

Implements Qore::AbstractIterator.