SQLite3Result::columnType

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

SQLite3Result::columnType — Returns the type of the nth column

说明

public SQLite3Result::columnType(int $column): int|false

Returns the type of the column identified by column.

参数

column: The numeric zero-based index of the column.

返回值

Returns the data type index of the column identified by column (one of SQLITE3_INTEGER, SQLITE3_FLOAT, SQLITE3_TEXT, SQLITE3_BLOB, or SQLITE3_NULL), or false if the column does not exist.

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phpnotes at carwash dot org ¶

13 years ago

This function never returns any value other than 5, indicating SQLITE3_NULL.  SQLite 3 doesn't have column types, it has column affinities.  Different rows of the same table (and rows resulting from a SELECT) can hold values of different types.  Therefore this API cannot return anything useful, and the method appears to be using SQLITE3_NULL as a placeholder. 

The function in useless and should be removed or marked as deprecated in future releases, so as not to give any programmer the false idea that the values returned are useful.

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hairbysubaru at gmail dot com ¶

8 years ago

jean-marc is correct. SQLite determines column types dynamically based upon the returned record-set.

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jean-marc at paratte dot ch ¶

10 years ago

To find the type of columns, you need to 'query' the SQL sentence, 'fetchArray' the 1rst row, and then extract the name and type of each column.

Example:

function _sqlite_fetch_all( $db, $sql ) {

    $sqlite = new SQLite3( $db);

    if( $sqlite->lastErrorCode() ) return;

    $result = $sqlite->query( $sql );

    $result->fetchArray( SQLITE3_NUM );
    $fieldnames = [];
    $fieldtypes = [];
    for( $colnum=0; $colnum<$result->numColumns(); $colnum++) {
        $fieldnames[] = $result->columnName($colnum);
        $fieldtypes[] = $result->columnType($colnum);
    }
    $result->reset();

    while( $row = $result->fetchArray( SQLITE3_NUM ) ) {

        for ($colnum=0; $colnum<count($row); $colnum++) {
            $col = &$row[$colnum];
            if (isset($fieldtype_encode_binary[$fieldtypes[$colnum]])) $col = $fieldtype_encode_binary[$fieldtypes[$colnum]]( $col );
        }
        unset($col);
        if ($resulttype == SQLITE3_ASSOC) $row = array_combine( $fieldnames, $row );
        $rows[] = $row;
    }

    $result->finalize();

    $sqlite->close();

    return $rows;
}

Remark 1: The type of a column is SQLITE3_NULL before any 'fetchArray' and 'false' after last fetched row.

Remark2 : The actual values of SQLITE3_INTEGER, SQLITE3_FLOAT, SQLITE3_TEXT, SQLITE3_BLOB, SQLITE3_NULL are 1, 2, 3, 4, 5.