** KEYWORDS: {column access functions}
** METHOD: sqlite3_stmt
**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
+** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
+** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
+** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
+** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
+** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
+** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
+** [sqlite3_value|unprotected sqlite3_value] object.
+** <tr><td> <td> <td>
+** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT result in bytes
+** <tr><td><b>sqlite3_column_bytes16 </b>
+** <td>→ <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
+** datatype of the result
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
** ^These routines return information about a single column of the current
** result row of a query. ^In every case the first argument is a pointer
** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
** are called from a different thread while any of these routines
** are pending, then the results are undefined.
**
+** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
+** each return the value of a result column in a specific data format. If
+** the result column is not initially in the requested format (for example,
+** if the query returns an integer but the sqlite3_column_text() interface
+** is used to extract the value) then an automatic type conversion is performed.
+**
** ^The sqlite3_column_type() routine returns the
** [SQLITE_INTEGER | datatype code] for the initial data type
** of the result column. ^The returned value is one of [SQLITE_INTEGER],
-** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
-** returned by sqlite3_column_type() is only meaningful if no type
-** conversions have occurred as described below. After a type conversion,
-** the value returned by sqlite3_column_type() is undefined. Future
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
+** The return value of sqlite3_column_type() can be used to decide which
+** of the first six interface should be used to extract the column value.
+** The value returned by sqlite3_column_type() is only meaningful if no
+** automatic type conversions have occurred for the value in question.
+** After a type conversion, the result of calling sqlite3_column_type()
+** is undefined, though harmless. Future
** versions of SQLite may change the behavior of sqlite3_column_type()
** following a type conversion.
**
+** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
+** or sqlite3_column_bytes16() interfaces can be used to determine the size
+** of that BLOB or string.
+**
** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
** routine returns the number of bytes in that BLOB or string.
** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
** [sqlite3_column_value()] is used in any other way, including calls
** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
** or [sqlite3_value_bytes()], the behavior is not threadsafe.
+** Hence, the sqlite3_column_value() interface
+** is normally only useful within the implementation of
+** [application-defined SQL functions] or [virtual tables], not within
+** top-level application code.
**
-** These routines attempt to convert the value where appropriate. ^For
-** example, if the internal representation is FLOAT and a text result
+** The these routines may attempt to convert the datatype of the result.
+** ^For example, if the internal representation is FLOAT and a text result
** is requested, [sqlite3_snprintf()] is used internally to perform the
** conversion automatically. ^(The following table details the conversions
** that are applied:
** ^The pointers returned are valid until a type conversion occurs as
** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
** [sqlite3_finalize()] is called. ^The memory space used to hold strings
-** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned
+** and BLOBs is freed automatically. Do not pass the pointers returned
** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
** [sqlite3_free()].
**
** [SQLITE_NOMEM].)^
*/
const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
-int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
-int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
double sqlite3_column_double(sqlite3_stmt*, int iCol);
int sqlite3_column_int(sqlite3_stmt*, int iCol);
sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
-int sqlite3_column_type(sqlite3_stmt*, int iCol);
sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+int sqlite3_column_type(sqlite3_stmt*, int iCol);
/*
** CAPI3REF: Destroy A Prepared Statement Object
** CAPI3REF: Obtaining SQL Values
** METHOD: sqlite3_value
**
-** The C-language implementation of SQL functions and aggregates uses
-** this set of interface routines to access the parameter values on
-** the function or aggregate.
-**
-** The xFunc (for scalar functions) or xStep (for aggregates) parameters
-** to [sqlite3_create_function()] and [sqlite3_create_function16()]
-** define callbacks that implement the SQL functions and aggregates.
-** The 3rd parameter to these callbacks is an array of pointers to
-** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
-** each parameter to the SQL function. These routines are used to
-** extract values from the [sqlite3_value] objects.
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
+** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
+** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
+** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
+** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
+** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
+** the native byteorder
+** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
+** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
+** <tr><td> <td> <td>
+** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT in bytes
+** <tr><td><b>sqlite3_value_bytes16 </b>
+** <td>→ <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
+** datatype of the value
+** <tr><td><b>sqlite3_value_numeric_type </b>
+** <td>→ <td>Best numeric datatype of the value
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** This routine extract type, size, and content information from
+** [protected sqlite3_value] objects. Protected sqlite3_value objects
+** are used to pass parameter information into implementation of
+** [application-defined SQL functions] and [virtual tables].
**
** These routines work only with [protected sqlite3_value] objects.
** Any attempt to use these routines on an [unprotected sqlite3_value]
-** object results in undefined behavior.
+** is not threadsafe.
**
** ^These routines work just like the corresponding [column access functions]
** except that these routines take a single [protected sqlite3_value] object
** the SQL function that supplied the [sqlite3_value*] parameters.
*/
const void *sqlite3_value_blob(sqlite3_value*);
-int sqlite3_value_bytes(sqlite3_value*);
-int sqlite3_value_bytes16(sqlite3_value*);
double sqlite3_value_double(sqlite3_value*);
int sqlite3_value_int(sqlite3_value*);
sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
const void *sqlite3_value_text16(sqlite3_value*);
const void *sqlite3_value_text16le(sqlite3_value*);
const void *sqlite3_value_text16be(sqlite3_value*);
+int sqlite3_value_bytes(sqlite3_value*);
+int sqlite3_value_bytes16(sqlite3_value*);
int sqlite3_value_type(sqlite3_value*);
int sqlite3_value_numeric_type(sqlite3_value*);
projects / thirdparty / sqlite.git / commitdiff
