/**************************************************************************
** Beginning of implementation of .fkey_missing_indexes
*/
-typedef struct PragmaVtab PragmaVtab;
-typedef struct PragmaCursor PragmaCursor;
-typedef struct PragmaConfig PragmaConfig;
/*
-** Table structure for "pragma" eponymous virtual tables.
-*/
-struct PragmaVtab {
- sqlite3_vtab base;
- PragmaConfig *pConfig;
- sqlite3 *db;
-};
-
-/*
-** Cursor structure for "pragma" eponymous virtual tables.
-*/
-struct PragmaCursor {
- sqlite3_vtab_cursor base;
- sqlite3_stmt *pSelect;
- sqlite3_stmt *pPragma;
- sqlite_int64 iRowid;
-};
-
-struct PragmaConfig {
- const char *zModule;
- const char *zSchema;
- const char *zPragma;
-};
-
-/*
-** Pragma virtual table module xConnect method.
-*/
-static int shellPragmaConnect(
- sqlite3 *db,
- void *pAux,
- int argc, const char *const*argv,
- sqlite3_vtab **ppVtab,
- char **pzErr
-){
- PragmaConfig *pConfig = (PragmaConfig*)pAux;
- PragmaVtab *pTab = 0;
- int rc;
-
- rc = sqlite3_declare_vtab(db, pConfig->zSchema);
- if( rc==SQLITE_OK ){
- pTab = (PragmaVtab*)sqlite3_malloc(sizeof(PragmaVtab));
- if( pTab==0 ){
- rc = SQLITE_NOMEM;
- }else{
- memset(pTab, 0, sizeof(PragmaVtab));
- pTab->db = db;
- pTab->pConfig = pConfig;
- }
- }else{
- *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
- }
-
- *ppVtab = (sqlite3_vtab*)pTab;
- return rc;
-}
-
-/*
-** Pragma virtual table module xDisconnect method.
-*/
-static int shellPragmaDisconnect(sqlite3_vtab *pVtab){
- PragmaVtab *pTab = (PragmaVtab*)pVtab;
- sqlite3_free(pTab);
- return SQLITE_OK;
-}
-
-/*
-** Pragma virtual table module xBestIndex method.
-*/
-static int shellPragmaBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
- return SQLITE_OK;
-}
-
-/*
-** Pragma virtual table module xOpen method.
-*/
-static int shellPragmaOpen(sqlite3_vtab *pVtab, sqlite3_vtab_cursor **ppCursor){
- PragmaCursor *pCsr;
-
- pCsr = (PragmaCursor*)sqlite3_malloc(sizeof(PragmaCursor));
- if( pCsr==0 ) return SQLITE_NOMEM;
- memset(pCsr, 0, sizeof(PragmaCursor));
- pCsr->base.pVtab = pVtab;
-
- *ppCursor = (sqlite3_vtab_cursor*)pCsr;
- return SQLITE_OK;
-}
-
-/*
-** Pragma virtual table module xClose method.
-*/
-static int shellPragmaClose(sqlite3_vtab_cursor *cur){
- return SQLITE_OK;
-}
-
-/*
-** Pragma virtual table module xNext method.
-*/
-static int shellPragmaNext(sqlite3_vtab_cursor *pVtabCursor){
- PragmaCursor *pCsr = (PragmaCursor*)pVtabCursor;
- PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
- sqlite3 *db = pTab->db;
- int rc = SQLITE_OK;
-
- /* Increment the xRowid value */
- pCsr->iRowid++;
-
- while( 1 ){
- assert( rc==SQLITE_OK );
-
- if( pCsr->pPragma ){
- if( SQLITE_ROW!=sqlite3_step(pCsr->pPragma) ){
- rc = sqlite3_finalize(pCsr->pPragma);
- pCsr->pPragma = 0;
- }
- }
-
- if( rc==SQLITE_OK && pCsr->pPragma==0 ){
- if( SQLITE_ROW!=sqlite3_step(pCsr->pSelect) ){
- rc = sqlite3_finalize(pCsr->pSelect);
- pCsr->pSelect = 0;
- }else{
- const char *zName = (const char*)sqlite3_column_text(pCsr->pSelect, 0);
- char *zSql = sqlite3_mprintf(pTab->pConfig->zPragma, zName);
- if( zSql==0 ){
- rc = SQLITE_NOMEM;
- }else{
- rc = sqlite3_prepare_v2(db, zSql, -1, &pCsr->pPragma, 0);
- if( rc!=SQLITE_OK ){
- pTab->base.zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
- }else{
- continue;
- }
- }
- }
- }
-
- break;
- }
-
- return rc;
-}
-
-/*
-** Pragma virtual table module xFilter method.
-*/
-static int shellPragmaFilter(
- sqlite3_vtab_cursor *pVtabCursor,
- int idxNum, const char *idxStr,
- int argc, sqlite3_value **argv
-){
- PragmaCursor *pCsr = (PragmaCursor*)pVtabCursor;
- PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
- int rc;
-
- sqlite3_finalize(pCsr->pSelect);
- sqlite3_finalize(pCsr->pPragma);
- pCsr->pSelect = 0;
- pCsr->pPragma = 0;
- pCsr->iRowid = 0;
-
- rc = sqlite3_prepare_v2(pTab->db,
- "SELECT name FROM sqlite_master WHERE type = 'table' AND rootpage>0",
- -1, &pCsr->pSelect, 0
- );
- if( rc!=SQLITE_OK ){
- pTab->base.zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
- return rc;
- }
-
- return shellPragmaNext(pVtabCursor);
-}
-
-/*
-** Pragma virtual table module xEof method.
-*/
-static int shellPragmaEof(sqlite3_vtab_cursor *pVtabCursor){
- PragmaCursor *pCsr = (PragmaCursor*)pVtabCursor;
- return (pCsr->pSelect==0);
-}
-
-/*
-** Pragma virtual table module xColumn method.
-*/
-static int shellPragmaColumn(
- sqlite3_vtab_cursor *pVtabCursor,
- sqlite3_context *ctx,
- int i
-){
- PragmaCursor *pCsr = (PragmaCursor*)pVtabCursor;
- switch( i ){
- case 0: /* "database" */
- sqlite3_result_text(ctx, "main", -1, SQLITE_STATIC);
- break;
-
- case 1: /* "child"/"table" */
- sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pSelect, 0));
- break;
-
- default:
- sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pPragma, i-2));
- break;
- }
-
- return SQLITE_OK;
-}
-
-/*
-** Pragma virtual table module xRowid method.
-*/
-static int shellPragmaRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *p){
- PragmaCursor *pCsr = (PragmaCursor*)pVtabCursor;
- *p = pCsr->iRowid;
- return SQLITE_OK;
-}
-
-/*
-** Register the virtual table module with the supplied database handle.
-*/
-static int shellPragmaRegister(sqlite3 *db){
- static sqlite3_module shellPragmaModule = {
- 0, /* iVersion */
- shellPragmaConnect, /* xCreate - create a table */
- shellPragmaConnect, /* xConnect - connect to an existing table */
- shellPragmaBestIndex, /* xBestIndex - Determine search strategy */
- shellPragmaDisconnect, /* xDisconnect - Disconnect from a table */
- shellPragmaDisconnect, /* xDestroy - Drop a table */
- shellPragmaOpen, /* xOpen - open a cursor */
- shellPragmaClose, /* xClose - close a cursor */
- shellPragmaFilter, /* xFilter - configure scan constraints */
- shellPragmaNext, /* xNext - advance a cursor */
- shellPragmaEof, /* xEof */
- shellPragmaColumn, /* xColumn - read data */
- shellPragmaRowid, /* xRowid - read data */
- 0, /* xUpdate - write data */
- 0, /* xBegin - begin transaction */
- 0, /* xSync - sync transaction */
- 0, /* xCommit - commit transaction */
- 0, /* xRollback - rollback transaction */
- 0, /* xFindFunction - function overloading */
- 0, /* xRename - rename the table */
- 0, /* xSavepoint */
- 0, /* xRelease */
- 0 /* xRollbackTo */
- };
- int rc = SQLITE_OK;
- int i;
-
- static PragmaConfig aConfig[] = {
- { "pragma_foreign_key_list",
- "CREATE TABLE x(database, child, "
- "id, seq, parent, child_col, parent_col, on_update, on_delete, match)",
- "PRAGMA foreign_key_list = %Q"
- },
- { "pragma_table_info",
- "CREATE TABLE x(database, tbl, "
- "cid, name, type, not_null, dflt_value, pk)",
- "PRAGMA table_info = %Q"
- }
- };
-
- for(i=0; rc==SQLITE_OK && i<sizeof(aConfig)/sizeof(aConfig[0]); i++){
- rc = sqlite3_create_module_v2(
- db, aConfig[i].zModule, &shellPragmaModule, (void*)&aConfig[i], 0
- );
- }
-
- return rc;
-}
-
-/*
-** The implementation of SQL scalar function fkey_collate_clause(). This
-** scalar function is always called with four arguments - the parent
-** table name, the parent column name, the child table name and the child
-** column name.
+** The implementation of SQL scalar function fkey_collate_clause(), used
+** by the ".fkey_missing_indexes" command. This scalar function is always
+** called with four arguments - the parent table name, the parent column name,
+** the child table name and the child column name.
**
** fkey_collate_clause('parent-tab', 'parent-col', 'child-tab', 'child-col')
**
char **azArg, /* Array of arguments passed to dot command */
int nArg /* Number of entries in azArg[] */
){
- sqlite3 *db = pState->db;
- FILE *out = pState->out;
+ 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;
- const char *zIndent = "";
-
- int rc;
- sqlite3_stmt *pSql = 0;
+ 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 rowid FROM child_table WHERE child_key=?"
+ **
+ ** This is the same SELECT 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 rowid FROM ' || quote(child) || ' WHERE ' "
- " || group_concat(quote(child) || '.' || quote(child_col) || '=?' || "
- " fkey_collate_clause(parent, parent_col, child, child_col),' AND ')"
+ "SELECT "
+ " 'EXPLAIN QUERY PLAN SELECT rowid FROM ' || quote(s.name) || ' WHERE '"
+ " || group_concat(quote(s.name) || '.' || quote(f.[from]) || '=?' "
+ " || fkey_collate_clause(f.[table], f.[to], s.name, f.[from]),' AND ')"
", "
- " 'SEARCH TABLE ' || child || ' USING COVERING INDEX*('"
+ " 'SEARCH TABLE ' || s.name || ' USING COVERING INDEX*('"
" || group_concat('*=?', ' AND ') || ')'"
", "
- " child || '(' || group_concat(child_col, ', ') || ')'"
+ " s.name || '(' || group_concat(f.[from], ', ') || ')'"
", "
- " parent || '(' || group_concat(COALESCE(parent_col, "
- " (SELECT name FROM pragma_table_info WHERE tbl=parent AND pk=seq+1)"
+ " f.[table] || '(' || group_concat(COALESCE(f.[to], "
+ " (SELECT name FROM pragma_table_info(f.[table]) WHERE pk=seq+1)"
" )) || ')'"
", "
- " 'CREATE INDEX ' || quote(child ||'_'|| group_concat(child_col, '_'))"
- " || ' ON ' || quote(child) || '('"
- " || group_concat(quote(child_col) ||"
- " fkey_collate_clause(parent, parent_col, child, child_col), ', ')"
+ " 'CREATE INDEX ' || quote(s.name ||'_'|| group_concat(f.[from], '_'))"
+ " || ' ON ' || quote(s.name) || '('"
+ " || group_concat(quote(f.[from]) ||"
+ " fkey_collate_clause(f.[table], f.[to], s.name, f.[from]), ', ')"
" || ');'"
", "
- " parent "
+ " f.[table] "
- "FROM pragma_foreign_key_list GROUP BY child, id "
- "ORDER BY (CASE WHEN ? THEN parent ELSE CHILD END)"
+ "FROM sqlite_master AS s, pragma_foreign_key_list(s.name) AS f "
+ "GROUP BY s.name, f.id "
+ "ORDER BY (CASE WHEN ? THEN f.[table] ELSE s.name END)"
;
for(i=1; i<nArg; i++){
return SQLITE_ERROR;
}
}
-
- /* Register the pragma eponymous virtual tables */
- rc = shellPragmaRegister(db);
/* Register the fkey_collate_clause() SQL function */
- if( rc==SQLITE_OK ){
- rc = sqlite3_create_function(db, "fkey_collate_clause", 4, SQLITE_UTF8,
- 0, shellFkeyCollateClause, 0, 0
- );
- }
+ rc = sqlite3_create_function(db, "fkey_collate_clause", 4, SQLITE_UTF8,
+ 0, shellFkeyCollateClause, 0, 0
+ );
if( rc==SQLITE_OK ){
projects / thirdparty / sqlite.git / commitdiff
