Function lintFkeyIndexes

modules/dasSQLITE/sqlite/shell.c:21635–21806

** The implementation of dot-command ".lint fkey-indexes". */

** The implementation of dot-command ".lint fkey-indexes".
*/
static int lintFkeyIndexes(
  ShellState *pState,             /* Current shell tool state */
  char **azArg,                   /* Array of arguments passed to dot command */
  int nArg                        /* Number of entries in azArg[] */
){
  sqlite3 *db = pState->db;       /* Database handle to query "main" db of */
  FILE *out = pState->out;        /* Stream to write non-error output to */
  int bVerbose = 0;               /* If -verbose is present */
  int bGroupByParent = 0;         /* If -groupbyparent is present */
  int i;                          /* To iterate through azArg[] */
  const char *zIndent = "";       /* How much to indent CREATE INDEX by */
  int rc;                         /* Return code */
  sqlite3_stmt *pSql = 0;         /* Compiled version of SQL statement below */

  /*
  ** This SELECT statement returns one row for each foreign key constraint
  ** in the schema of the main database. The column values are:
  **
  ** 0. The text of an SQL statement similar to:
  **
  **      "EXPLAIN QUERY PLAN SELECT 1 FROM child_table WHERE child_key=?"
  **
  **    This SELECT is similar to the one that the foreign keys implementation
  **    needs to run internally on child tables. If there is an index that can
  **    be used to optimize this query, then it can also be used by the FK
  **    implementation to optimize DELETE or UPDATE statements on the parent
  **    table.
  **
  ** 1. A GLOB pattern suitable for sqlite3_strglob(). If the plan output by
  **    the EXPLAIN QUERY PLAN command matches this pattern, then the schema
  **    contains an index that can be used to optimize the query.
  **
  ** 2. Human readable text that describes the child table and columns. e.g.
  **
  **       "child_table(child_key1, child_key2)"
  **
  ** 3. Human readable text that describes the parent table and columns. e.g.
  **
  **       "parent_table(parent_key1, parent_key2)"
  **
  ** 4. A full CREATE INDEX statement for an index that could be used to
  **    optimize DELETE or UPDATE statements on the parent table. e.g.
  **
  **       "CREATE INDEX child_table_child_key ON child_table(child_key)"
  **
  ** 5. The name of the parent table.
  **
  ** These six values are used by the C logic below to generate the report.
  */
  const char *zSql =
  "SELECT "
    "     'EXPLAIN QUERY PLAN SELECT 1 FROM ' || quote(s.name) || ' WHERE '"
    "  || group_concat(quote(s.name) || '.' || quote(f.[from]) || '=?' "
    "  || fkey_collate_clause("
    "       f.[table], COALESCE(f.[to], p.[name]), s.name, f.[from]),' AND ')"
    ", "
    "     'SEARCH ' || s.name || ' USING COVERING INDEX*('"
    "  || group_concat('*=?', ' AND ') || ')'"