C API prepared insert truncates strings to 5 characters
Posted by: 7 reeds
Date: March 18, 2013 02:31PM

Hi,

I have written a couple of small C API programs in the past but this is my first time to use prepared statements. What I am doing compiles and runs but the resulting strings in the target table are all chopped to 5 characters.

I can not see what would limit the string length in the code

The target table:

mysql> describe log;
+--------------+------------------+------+-----+---------+----------------+
| Field        | Type             | Null | Key | Default | Extra          |
+--------------+------------------+------+-----+---------+----------------+
| id           | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| machine      | varchar(64)      | NO   | MUL | NULL    |                |
| date         | datetime         | NO   | MUL | NULL    |                |
| event        | varchar(8)       | NO   | MUL | NULL    |                |
| netid        | varchar(16)      | NO   | MUL | NULL    |                |
| domain       | varchar(32)      | NO   | MUL | NULL    |                |
| line         | varchar(64)      | NO   | MUL | NULL    |                |
| source       | varchar(8)       | NO   | MUL | NULL    |                |
| dateInserted | datetime         | NO   | MUL | NULL    |                |
| notes        | varchar(128)     | NO   |     | NULL    |                |
+--------------+------------------+------+-----+---------+----------------+

The insert code:

int insertIntoDB(MYSQL *mysql, struct env PEnv, char *date, char *source) {

    char *insertSQL = "\
INSERT INTO personalDB.log \
            (id, event, machine, netid, line, source, date) \
VALUES(NULL, UPPER(?), UPPER(?), UPPER(?), UPPER(?), UPPER(?), NOW())";

    char *tmp;
    char *datePtr;

    int numBindCols = 5;
    int col = 0;

    int result = 0;

    unsigned long bufferLength = 0;

    MYSQL_STMT *sth;

    if (DEBUG) {
        syslog(LOG_AUTHPRIV | LOG_INFO, "insertIntoDB: start");
    }

    /*
     * "date" will usually be NULL. If not NULL it will be in ISO std
     * YYYY-MM-DD HH:mm:SS format.  If we have a date string, modify the 
     * insert statement to accept a bind value for the date -- i.e. replace
     * the "NOW()" in the insert string with a "?"
     */

    if (date != NULL ) {
        tmp = strstr(insertSQL, "NOW())");
        if (tmp != NULL ) {
            tmp = "?)";
            numBindCols++;
        }
    }

    /*
     * setup the statement
     */

    if ((sth = mysql_stmt_init(mysql)) != NULL ) {
        /*
         * setup the prepare
         */
        if (mysql_stmt_prepare(sth, insertSQL, strlen(insertSQL)) == 0) {
            MYSQL_BIND bind[numBindCols];
            memset(bind, 0, sizeof(bind));

            bind[col].buffer_type = MYSQL_TYPE_STRING;
            bind[col].buffer = (void *) PEnv.event;
            bind[col].is_unsigned = 0;
            bind[col].is_null = 0;
            bind[col].buffer_length = 8;
            bufferLength = strlen(PEnv.event);
            bind[col++].length = &bufferLength;
            if (DEBUG) {
                syslog(LOG_AUTHPRIV | LOG_INFO,
                        "insertIntoDB: event=%s/%lu", PEnv.event,
                        bufferLength);
            }

            bind[col].buffer_type = MYSQL_TYPE_STRING;
            bind[col].buffer = (void *) PEnv.rhost;
            bind[col].is_unsigned = 0;
            bind[col].is_null = 0;
            bind[col].buffer_length = 64;
            bufferLength = strlen(PEnv.rhost);
            bind[col++].length = &bufferLength;
            if (DEBUG) {
                syslog(LOG_AUTHPRIV | LOG_INFO,
                        "insertIntoDB: rhost=%s/%lu", PEnv.rhost,
                        bufferLength);
            }

            bind[col].buffer_type = MYSQL_TYPE_STRING;
            bind[col].buffer = (void *) PEnv.user;
            bind[col].is_unsigned = 0;
            bind[col].is_null = 0;
            bind[col].buffer_length = 16;
            bufferLength = strlen(PEnv.user);
            bind[col++].length = &bufferLength;
            if (DEBUG) {
                syslog(LOG_AUTHPRIV | LOG_INFO,
                        "insertIntoDB: user=%s/%lu", PEnv.user,
                        bufferLength);
            }

            bind[col].buffer_type = MYSQL_TYPE_STRING;
            bind[col].buffer = (void *) PEnv.service;
            bind[col].is_unsigned = 0;
            bind[col].is_null = 0;
            bind[col].buffer_length = 64;
            bufferLength = strlen(PEnv.service);
            bind[col++].length = &bufferLength;
            if (DEBUG) {
                syslog(LOG_AUTHPRIV | LOG_INFO,
                        "insertIntoDB: service=%s/%lu",
                        PEnv.service, bufferLength);
            }

            bind[col].buffer_type = MYSQL_TYPE_STRING;
            bind[col].buffer = (void *) source;
            bind[col].is_unsigned = 0;
            bind[col].is_null = 0;
            bind[col].buffer_length = 8;
            bufferLength = strlen(source);
            bind[col++].length = &bufferLength;
            if (DEBUG) {
                syslog(LOG_AUTHPRIV | LOG_INFO,
                        "insertIntoDB: source=%s/%lu", source,
                        bufferLength);
            }

            /*
             * do we have a date string?
             * ... I've not tested this section yet, not sure if the 
             * strtol's will do what I want ...
             */
            if (numBindCols > col) {
                if (DEBUG) {
                    syslog(LOG_AUTHPRIV | LOG_INFO,
                            "insertIntoDB: numBindCols=%d,col=%d",
                            numBindCols, col);
                }

                MYSQL_TIME localDate;
                localDate.year = strtol(date, &datePtr, 10);
                datePtr++;
                localDate.month = strtol(datePtr, &datePtr, 10);
                datePtr++;
                localDate.day = strtol(datePtr, &datePtr, 10);
                datePtr++;
                localDate.hour = strtol(datePtr, &datePtr, 10);
                datePtr++;
                localDate.minute = strtol(datePtr, &datePtr, 10);
                datePtr++;
                localDate.second = strtol(datePtr, &datePtr, 10);

                bind[col].buffer_type = MYSQL_TYPE_DATETIME;
                bind[col].buffer = &localDate;
                bind[col].is_unsigned = 0;
                bind[col].is_null = 0;
                bufferLength = sizeof(localDate);
                bind[col++].length = &bufferLength;
                if (DEBUG) {
                    syslog(LOG_AUTHPRIV | LOG_INFO,
                            "insertIntoDB: date=%s/%lu", date,
                            bufferLength);
                }
            }

            if (mysql_stmt_bind_param(sth, bind) == 0) {
                if (mysql_stmt_execute(sth) != 0) {
                    syslog(LOG_AUTHPRIV | LOG_INFO,
                            "insertIntoDB: MySQL could not execute: %s",
                            mysql_stmt_error(sth));
                    result = __LINE__;
                }
            } else {
                syslog(LOG_AUTHPRIV | LOG_INFO,
                        "insertIntoDB: MySQL could not bind values: %s",
                        mysql_stmt_error(sth));
                result = __LINE__;
            }
        } else {
            syslog(LOG_AUTHPRIV | LOG_INFO,
                    "insertIntoDB: MySQL could not prepare query: %s",
                    mysql_stmt_error(sth));
            result = __LINE__;
        }

        mysql_stmt_free_result(sth);
        mysql_stmt_close(sth);
    } else {
        syslog(LOG_AUTHPRIV | LOG_INFO,
                "insertIntoDB: MySQL could not init statement: %s",
                mysql_stmt_error(sth));
        result = __LINE__;
    }

    if (DEBUG) {
        syslog(LOG_AUTHPRIV | LOG_INFO, "insertIntoDB: end");
    }

    return result;
}

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C API prepared insert truncates strings to 5 characters
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March 18, 2013 02:31PM


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