select.c

/*!
 * \file db/dbmi_client/select.c
 *
 * \brief DBMI Library (client) - select records from table
 *
 * (C) 1999-2008 by the GRASS Development Team
 *
 * This program is free software under the GNU General Public
 * License (>=v2). Read the file COPYING that comes with GRASS
 * for details.
 *
 * \author Joel Jones (CERL/UIUC), Radim Blazek
 */

#include <stdlib.h>
#include <string.h>
#include <grass/gis.h>
#include <grass/dbmi.h>
#include <grass/glocale.h>

static int cmp(const void *pa, const void *pb)
{
    int *p1 = (int *)pa;
    int *p2 = (int *)pb;

    if (*p1 < *p2)
        return -1;
    if (*p1 > *p2)
        return 1;
    return 0;
}

static int cmpcat(const void *pa, const void *pb)
{
    dbCatVal *p1 = (dbCatVal *)pa;
    dbCatVal *p2 = (dbCatVal *)pb;

    if (p1->cat < p2->cat)
        return -1;
    if (p1->cat > p2->cat)
        return 1;
    return 0;
}

static int cmpcatkey(const void *pa, const void *pb)
{
    int *p1 = (int *)pa;
    dbCatVal *p2 = (dbCatVal *)pb;

    if (*p1 < p2->cat)
        return -1;
    if (*p1 > p2->cat)
        return 1;
    return 0;
}

static int cmpvalueint(const void *pa, const void *pb)
{
    dbCatVal *p1 = (dbCatVal *)pa;
    dbCatVal *p2 = (dbCatVal *)pb;

    if (p1->val.i < p2->val.i)
        return -1;
    if (p1->val.i > p2->val.i)
        return 1;

    return 0;
}

static int cmpvaluedouble(const void *pa, const void *pb)
{
    dbCatVal *p1 = (dbCatVal *)pa;
    dbCatVal *p2 = (dbCatVal *)pb;

    if (p1->val.d < p2->val.d)
        return -1;
    if (p1->val.d > p2->val.d)
        return 1;

    return 0;
}

static int cmpvaluestring(const void *pa, const void *pb)
{
    dbCatVal *const *a = pa;
    dbCatVal *const *b = pb;

    return strcmp((const char *)a, (const char *)b);
}

/*!
   \brief Select array of ordered integers from table/column

   \param driver DB driver
   \param tab table name
   \param col column name
   \param where where statement
   \param[out] pval array of ordered integer values

   \return number of selected values
   \return -1 on error
 */
int db_select_int(dbDriver *driver, const char *tab, const char *col,
                  const char *where, int **pval)
{
    int type, more, alloc, count;
    int *val;
    char *buf = NULL;
    const char *sval;
    dbString stmt;
    dbCursor cursor;
    dbColumn *column;
    dbValue *value;
    dbTable *table;

    G_debug(3, "db_select_int()");

    if (col == NULL || strlen(col) == 0) {
        G_warning(_("Missing column name"));
        return -1;
    }

    /* allocate */
    alloc = 1000;
    val = (int *)G_malloc(alloc * sizeof(int));

    if (where == NULL || strlen(where) == 0)
        G_asprintf(&buf, "SELECT %s FROM %s", col, tab);
    else
        G_asprintf(&buf, "SELECT %s FROM %s WHERE %s", col, tab, where);

    G_debug(3, "  SQL: %s", buf);

    db_init_string(&stmt);
    db_set_string(&stmt, buf);
    G_free(buf);

    if (db_open_select_cursor(driver, &stmt, &cursor, DB_SEQUENTIAL) != DB_OK)
        return (-1);

    table = db_get_cursor_table(&cursor);
    column = db_get_table_column(table, 0); /* first column */
    if (column == NULL) {
        return -1;
    }
    value = db_get_column_value(column);
    type = db_get_column_sqltype(column);
    type = db_sqltype_to_Ctype(type);

    /* fetch the data */
    count = 0;
    while (1) {
        if (db_fetch(&cursor, DB_NEXT, &more) != DB_OK)
            return (-1);

        if (!more)
            break;

        if (count == alloc) {
            alloc += 1000;
            val = (int *)G_realloc(val, alloc * sizeof(int));
        }

        switch (type) {
        case (DB_C_TYPE_INT):
            val[count] = db_get_value_int(value);
            break;
        case (DB_C_TYPE_STRING):
            sval = db_get_value_string(value);
            val[count] = atoi(sval);
            break;
        case (DB_C_TYPE_DOUBLE):
            val[count] = (int)db_get_value_double(value);
            break;
        default:
            return (-1);
        }
        count++;
    }

    db_close_cursor(&cursor);
    db_free_string(&stmt);

    qsort((void *)val, count, sizeof(int), cmp);

    *pval = val;

    return (count);
}

/*!
   \brief Select one (first) value from table/column for key/id

   \param driver DB driver
   \param tab table name
   \param key key column name
   \param id identifier in key column
   \param col name of column to select the value from
   \param[out] val dbValue to store within

   \return number of selected values
   \return -1 on error
 */
int db_select_value(dbDriver *driver, const char *tab, const char *key, int id,
                    const char *col, dbValue *val)
{
    int more, count;
    char *buf = NULL;
    dbString stmt;
    dbCursor cursor;
    dbColumn *column;
    dbValue *value;
    dbTable *table;

    if (key == NULL || strlen(key) == 0) {
        G_warning(_("Missing key column name"));
        return -1;
    }

    if (col == NULL || strlen(col) == 0) {
        G_warning(_("Missing column name"));
        return -1;
    }

    G_zero(val, sizeof(dbValue));
    G_asprintf(&buf, "SELECT %s FROM %s WHERE %s = %d", col, tab, key, id);
    db_init_string(&stmt);
    db_set_string(&stmt, buf);
    G_free(buf);

    if (db_open_select_cursor(driver, &stmt, &cursor, DB_SEQUENTIAL) != DB_OK)
        return (-1);

    table = db_get_cursor_table(&cursor);
    column = db_get_table_column(table, 0); /* first column */
    value = db_get_column_value(column);

    /* fetch the data */
    count = 0;
    while (1) {
        if (db_fetch(&cursor, DB_NEXT, &more) != DB_OK)
            return (-1);

        if (!more)
            break;
        if (count == 0)
            db_copy_value(val, value);
        count++;
    }
    db_close_cursor(&cursor);
    db_free_string(&stmt);

    return (count);
}

/*!
   \brief Select pairs key/value to array, values are sorted by key (must be
   integer)

   \param driver DB driver
   \param tab table name
   \param key key column name
   \param col value column name
   \param[out] cvarr dbCatValArray to store within

   \return number of selected values
   \return -1 on error
 */
int db_select_CatValArray(dbDriver *driver, const char *tab, const char *key,
                          const char *col, const char *where,
                          dbCatValArray *cvarr)
{
    int i, type, more, nrows, ncols;
    char *buf = NULL;
    dbString stmt;
    dbCursor cursor;
    dbColumn *column;
    dbValue *value;
    dbTable *table;

    G_debug(3, "db_select_CatValArray ()");

    if (key == NULL || strlen(key) == 0) {
        G_warning(_("Missing key column name"));
        return -1;
    }

    if (col == NULL || strlen(col) == 0) {
        G_warning(_("Missing column name"));
        return -1;
    }
    db_init_string(&stmt);

    if (strcmp(key, col) == 0) {
        ncols = 1;
        G_asprintf(&buf, "SELECT %s FROM %s", key, tab);
    }
    else {
        ncols = 2;
        G_asprintf(&buf, "SELECT %s, %s FROM %s", key, col, tab);
    }
    db_set_string(&stmt, buf);
    G_free(buf);

    if (where != NULL && strlen(where) > 0) {
        db_append_string(&stmt, " WHERE ");
        db_append_string(&stmt, where);
    }

    G_debug(3, "  SQL: %s", db_get_string(&stmt));

    if (db_open_select_cursor(driver, &stmt, &cursor, DB_SEQUENTIAL) != DB_OK)
        return (-1);

    nrows = db_get_num_rows(&cursor);
    G_debug(3, "  %d rows selected", nrows);
    if (nrows < 0) {
        G_warning(_("Unable select records from table <%s>"), tab);
        db_close_cursor(&cursor);
        db_free_string(&stmt);
        return -1;
    }

    db_CatValArray_alloc(cvarr, nrows);

    table = db_get_cursor_table(&cursor);

    /* Check if key column is integer */
    column = db_get_table_column(table, 0);
    type = db_sqltype_to_Ctype(db_get_column_sqltype(column));
    G_debug(3, "  key type = %d", type);

    if (type != DB_C_TYPE_INT) {
        G_warning(_("Key column type is not integer"));
        db_close_cursor(&cursor);
        db_free_string(&stmt);
        return -1;
    }

    if (ncols == 2) {
        column = db_get_table_column(table, 1);
        type = db_sqltype_to_Ctype(db_get_column_sqltype(column));
        G_debug(3, "  col type = %d", type);

        /*
           if ( type != DB_C_TYPE_INT && type != DB_C_TYPE_DOUBLE ) {
           G_fatal_error ( "Column type not supported by db_select_to_array()"
           );
           }
         */
    }
    cvarr->ctype = type;

    /* fetch the data */
    for (i = 0; i < nrows; i++) {
        if (db_fetch(&cursor, DB_NEXT, &more) != DB_OK)
            return (-1);

        column = db_get_table_column(table, 0); /* first column */
        value = db_get_column_value(column);
        cvarr->value[i].cat = db_get_value_int(value);

        if (ncols == 2) {
            column = db_get_table_column(table, 1);
            value = db_get_column_value(column);
        }
        cvarr->value[i].isNull = value->isNull;
        switch (type) {
        case (DB_C_TYPE_INT):
            if (value->isNull)
                cvarr->value[i].val.i = 0;
            else
                cvarr->value[i].val.i = db_get_value_int(value);
            break;

        case (DB_C_TYPE_DOUBLE):
            if (value->isNull)
                cvarr->value[i].val.d = 0.0;
            else
                cvarr->value[i].val.d = db_get_value_double(value);
            break;

        case (DB_C_TYPE_STRING):
            cvarr->value[i].val.s = (dbString *)malloc(sizeof(dbString));
            db_init_string(cvarr->value[i].val.s);

            if (!(value->isNull))
                db_set_string(cvarr->value[i].val.s,
                              db_get_value_string(value));
            break;

        case (DB_C_TYPE_DATETIME):
            cvarr->value[i].val.t = (dbDateTime *)calloc(1, sizeof(dbDateTime));

            if (!(value->isNull))
                memcpy(cvarr->value[i].val.t, &(value->t), sizeof(dbDateTime));
            break;

        default:
            return (-1);
        }
    }
    cvarr->n_values = nrows;

    db_close_cursor(&cursor);
    db_free_string(&stmt);

    db_CatValArray_sort(cvarr);

    return nrows;
}

/*!
   \brief Sort key/value array by key
   \param[in,out] arr dbCatValArray (key/value array)
 */
void db_CatValArray_sort(dbCatValArray *arr)
{
    qsort((void *)arr->value, arr->n_values, sizeof(dbCatVal), cmpcat);
}

/*!
   \brief Sort key/value array by value

   \param[in,out] arr dbCatValArray (key/value array)

   \return DB_OK on success
   \return DB_FAILED on error
 */
int db_CatValArray_sort_by_value(dbCatValArray *arr)
{
    switch (arr->ctype) {
    case (DB_C_TYPE_INT):
        qsort((void *)arr->value, arr->n_values, sizeof(dbCatVal), cmpvalueint);
        break;
    case (DB_C_TYPE_DOUBLE):
        qsort((void *)arr->value, arr->n_values, sizeof(dbCatVal),
              cmpvaluedouble);
        break;
    case (DB_C_TYPE_STRING):
        qsort((void *)arr->value, arr->n_values, sizeof(dbCatVal),
              cmpvaluestring);
        break;
    case (DB_C_TYPE_DATETIME): /* is cmpvaluestring right here ? */
        qsort((void *)arr->value, arr->n_values, sizeof(dbCatVal),
              cmpvaluestring);
        break;
    default:
        return (DB_FAILED);
    }

    return (DB_OK);
}

/*!
   \brief Find value by key

   \param arr dbCatValArray (key/value array)
   \param key key value
   \param[out] cv dbCatVal structure (key/value) to store within

   \return DB_OK on success
   \return DB_FAILED on error
 */
int db_CatValArray_get_value(dbCatValArray *arr, int key, dbCatVal **cv)
{
    dbCatVal *catval;

    catval = bsearch((void *)&key, arr->value, arr->n_values, sizeof(dbCatVal),
                     cmpcat);
    if (catval == NULL) {
        return DB_FAILED;
    }

    *cv = catval;

    return DB_OK;
}

/*!
   \brief Find value (integer) by key

   \param arr dbCatValArray (key/value array)
   \param key key value
   \param[out] val found value (integer)

   \return DB_OK on success
   \return DB_FAILED on error
 */
int db_CatValArray_get_value_int(dbCatValArray *arr, int key, int *val)
{
    dbCatVal *catval;

    catval = bsearch((void *)&key, arr->value, arr->n_values, sizeof(dbCatVal),
                     cmpcat);
    if (catval == NULL) {
        return DB_FAILED;
    }

    *val = catval->val.i;

    return DB_OK;
}

/*!
   \brief Find value (double) by key

   \param arr dbCatValArray (key/value array)
   \param key key value
   \param[out] val found value (double)

   \return DB_OK on success
   \return DB_FAILED on error
 */
int db_CatValArray_get_value_double(dbCatValArray *arr, int key, double *val)
{
    dbCatVal *catval;

    G_debug(3, "db_CatValArray_get_value_double(), key = %d", key);

    catval = bsearch((void *)&key, arr->value, arr->n_values, sizeof(dbCatVal),
                     cmpcatkey);
    if (catval == NULL) {
        return DB_FAILED;
    }

    *val = catval->val.d;

    return DB_OK;
}