1 /* 2 ** 2013-11-12 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** 13 ** This file contains structure and macro definitions for the query 14 ** planner logic in "where.c". These definitions are broken out into 15 ** a separate source file for easier editing. 16 */ 17 18 /* 19 ** Trace output macros 20 */ 21 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) 22 /***/ int sqlite3WhereTrace; 23 #endif 24 #if defined(SQLITE_DEBUG) \ 25 && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE)) 26 # define WHERETRACE(K,X) if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X 27 # define WHERETRACE_ENABLED 1 28 #else 29 # define WHERETRACE(K,X) 30 #endif 31 32 /* Forward references 33 */ 34 typedef struct WhereClause WhereClause; 35 typedef struct WhereMaskSet WhereMaskSet; 36 typedef struct WhereOrInfo WhereOrInfo; 37 typedef struct WhereAndInfo WhereAndInfo; 38 typedef struct WhereLevel WhereLevel; 39 typedef struct WhereLoop WhereLoop; 40 typedef struct WherePath WherePath; 41 typedef struct WhereTerm WhereTerm; 42 typedef struct WhereLoopBuilder WhereLoopBuilder; 43 typedef struct WhereScan WhereScan; 44 typedef struct WhereOrCost WhereOrCost; 45 typedef struct WhereOrSet WhereOrSet; 46 47 /* 48 ** This object contains information needed to implement a single nested 49 ** loop in WHERE clause. 50 ** 51 ** Contrast this object with WhereLoop. This object describes the 52 ** implementation of the loop. WhereLoop describes the algorithm. 53 ** This object contains a pointer to the WhereLoop algorithm as one of 54 ** its elements. 55 ** 56 ** The WhereInfo object contains a single instance of this object for 57 ** each term in the FROM clause (which is to say, for each of the 58 ** nested loops as implemented). The order of WhereLevel objects determines 59 ** the loop nested order, with WhereInfo.a[0] being the outer loop and 60 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. 61 */ 62 struct WhereLevel { 63 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ 64 int iTabCur; /* The VDBE cursor used to access the table */ 65 int iIdxCur; /* The VDBE cursor used to access pIdx */ 66 int addrBrk; /* Jump here to break out of the loop */ 67 int addrNxt; /* Jump here to start the next IN combination */ 68 int addrSkip; /* Jump here for next iteration of skip-scan */ 69 int addrCont; /* Jump here to continue with the next loop cycle */ 70 int addrFirst; /* First instruction of interior of the loop */ 71 int addrBody; /* Beginning of the body of this loop */ 72 int iLikeRepCntr; /* LIKE range processing counter register */ 73 int addrLikeRep; /* LIKE range processing address */ 74 u8 iFrom; /* Which entry in the FROM clause */ 75 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 76 int p1, p2; /* Operands of the opcode used to ends the loop */ 77 union { /* Information that depends on pWLoop->wsFlags */ 78 struct { 79 int nIn; /* Number of entries in aInLoop[] */ 80 struct InLoop { 81 int iCur; /* The VDBE cursor used by this IN operator */ 82 int addrInTop; /* Top of the IN loop */ 83 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 84 } *aInLoop; /* Information about each nested IN operator */ 85 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 86 Index *pCovidx; /* Possible covering index for WHERE_MULTI_OR */ 87 } u; 88 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 89 Bitmask notReady; /* FROM entries not usable at this level */ 90 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 91 int addrVisit; /* Address at which row is visited */ 92 #endif 93 }; 94 95 /* 96 ** Each instance of this object represents an algorithm for evaluating one 97 ** term of a join. Every term of the FROM clause will have at least 98 ** one corresponding WhereLoop object (unless INDEXED BY constraints 99 ** prevent a query solution - which is an error) and many terms of the 100 ** FROM clause will have multiple WhereLoop objects, each describing a 101 ** potential way of implementing that FROM-clause term, together with 102 ** dependencies and cost estimates for using the chosen algorithm. 103 ** 104 ** Query planning consists of building up a collection of these WhereLoop 105 ** objects, then computing a particular sequence of WhereLoop objects, with 106 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 107 ** and that minimize the overall cost. 108 */ 109 struct WhereLoop { 110 Bitmask prereq; /* Bitmask of other loops that must run first */ 111 Bitmask maskSelf; /* Bitmask identifying table iTab */ 112 #ifdef SQLITE_DEBUG 113 char cId; /* Symbolic ID of this loop for debugging use */ 114 #endif 115 u8 iTab; /* Position in FROM clause of table for this loop */ 116 u8 iSortIdx; /* Sorting index number. 0==None */ 117 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 118 LogEst rRun; /* Cost of running each loop */ 119 LogEst nOut; /* Estimated number of output rows */ 120 union { 121 struct { /* Information for internal btree tables */ 122 u16 nEq; /* Number of equality constraints */ 123 Index *pIndex; /* Index used, or NULL */ 124 } btree; 125 struct { /* Information for virtual tables */ 126 int idxNum; /* Index number */ 127 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ 128 i8 isOrdered; /* True if satisfies ORDER BY */ 129 u16 omitMask; /* Terms that may be omitted */ 130 char *idxStr; /* Index identifier string */ 131 } vtab; 132 } u; 133 u32 wsFlags; /* WHERE_* flags describing the plan */ 134 u16 nLTerm; /* Number of entries in aLTerm[] */ 135 u16 nSkip; /* Number of NULL aLTerm[] entries */ 136 /**** whereLoopXfer() copies fields above ***********************/ 137 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 138 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 139 WhereTerm **aLTerm; /* WhereTerms used */ 140 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 141 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 142 }; 143 144 /* This object holds the prerequisites and the cost of running a 145 ** subquery on one operand of an OR operator in the WHERE clause. 146 ** See WhereOrSet for additional information 147 */ 148 struct WhereOrCost { 149 Bitmask prereq; /* Prerequisites */ 150 LogEst rRun; /* Cost of running this subquery */ 151 LogEst nOut; /* Number of outputs for this subquery */ 152 }; 153 154 /* The WhereOrSet object holds a set of possible WhereOrCosts that 155 ** correspond to the subquery(s) of OR-clause processing. Only the 156 ** best N_OR_COST elements are retained. 157 */ 158 #define N_OR_COST 3 159 struct WhereOrSet { 160 u16 n; /* Number of valid a[] entries */ 161 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 162 }; 163 164 /* 165 ** Each instance of this object holds a sequence of WhereLoop objects 166 ** that implement some or all of a query plan. 167 ** 168 ** Think of each WhereLoop object as a node in a graph with arcs 169 ** showing dependencies and costs for travelling between nodes. (That is 170 ** not a completely accurate description because WhereLoop costs are a 171 ** vector, not a scalar, and because dependencies are many-to-one, not 172 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 173 ** Then a WherePath object is a path through the graph that visits some 174 ** or all of the WhereLoop objects once. 175 ** 176 ** The "solver" works by creating the N best WherePath objects of length 177 ** 1. Then using those as a basis to compute the N best WherePath objects 178 ** of length 2. And so forth until the length of WherePaths equals the 179 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 180 ** at the end is the chosen query plan. 181 */ 182 struct WherePath { 183 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 184 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 185 LogEst nRow; /* Estimated number of rows generated by this path */ 186 LogEst rCost; /* Total cost of this path */ 187 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 188 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 189 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 190 }; 191 192 /* 193 ** The query generator uses an array of instances of this structure to 194 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 195 ** clause subexpression is separated from the others by AND operators, 196 ** usually, or sometimes subexpressions separated by OR. 197 ** 198 ** All WhereTerms are collected into a single WhereClause structure. 199 ** The following identity holds: 200 ** 201 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 202 ** 203 ** When a term is of the form: 204 ** 205 ** X <op> <expr> 206 ** 207 ** where X is a column name and <op> is one of certain operators, 208 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 209 ** cursor number and column number for X. WhereTerm.eOperator records 210 ** the <op> using a bitmask encoding defined by WO_xxx below. The 211 ** use of a bitmask encoding for the operator allows us to search 212 ** quickly for terms that match any of several different operators. 213 ** 214 ** A WhereTerm might also be two or more subterms connected by OR: 215 ** 216 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 217 ** 218 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 219 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 220 ** is collected about the OR clause. 221 ** 222 ** If a term in the WHERE clause does not match either of the two previous 223 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 224 ** to the original subexpression content and wtFlags is set up appropriately 225 ** but no other fields in the WhereTerm object are meaningful. 226 ** 227 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 228 ** but they do so indirectly. A single WhereMaskSet structure translates 229 ** cursor number into bits and the translated bit is stored in the prereq 230 ** fields. The translation is used in order to maximize the number of 231 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 232 ** spread out over the non-negative integers. For example, the cursor 233 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 234 ** translates these sparse cursor numbers into consecutive integers 235 ** beginning with 0 in order to make the best possible use of the available 236 ** bits in the Bitmask. So, in the example above, the cursor numbers 237 ** would be mapped into integers 0 through 7. 238 ** 239 ** The number of terms in a join is limited by the number of bits 240 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 241 ** is only able to process joins with 64 or fewer tables. 242 */ 243 struct WhereTerm { 244 Expr *pExpr; /* Pointer to the subexpression that is this term */ 245 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 246 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 247 union { 248 int leftColumn; /* Column number of X in "X <op> <expr>" */ 249 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 250 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 251 } u; 252 LogEst truthProb; /* Probability of truth for this expression */ 253 u16 eOperator; /* A WO_xx value describing <op> */ 254 u16 wtFlags; /* TERM_xxx bit flags. See below */ 255 u8 nChild; /* Number of children that must disable us */ 256 WhereClause *pWC; /* The clause this term is part of */ 257 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 258 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 259 }; 260 261 /* 262 ** Allowed values of WhereTerm.wtFlags 263 */ 264 #define TERM_DYNAMIC 0x01 /* Need to call sqlite3ExprDelete(db, pExpr) */ 265 #define TERM_VIRTUAL 0x02 /* Added by the optimizer. Do not code */ 266 #define TERM_CODED 0x04 /* This term is already coded */ 267 #define TERM_COPIED 0x08 /* Has a child */ 268 #define TERM_ORINFO 0x10 /* Need to free the WhereTerm.u.pOrInfo object */ 269 #define TERM_ANDINFO 0x20 /* Need to free the WhereTerm.u.pAndInfo obj */ 270 #define TERM_OR_OK 0x40 /* Used during OR-clause processing */ 271 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 272 # define TERM_VNULL 0x80 /* Manufactured x>NULL or x<=NULL term */ 273 #else 274 # define TERM_VNULL 0x00 /* Disabled if not using stat3 */ 275 #endif 276 #define TERM_LIKEOPT 0x100 /* Virtual terms from the LIKE optimization */ 277 #define TERM_LIKECOND 0x200 /* Conditionally this LIKE operator term */ 278 #define TERM_LIKE 0x400 /* The original LIKE operator */ 279 #define TERM_IS 0x800 /* Term.pExpr is an IS operator */ 280 281 /* 282 ** An instance of the WhereScan object is used as an iterator for locating 283 ** terms in the WHERE clause that are useful to the query planner. 284 */ 285 struct WhereScan { 286 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 287 WhereClause *pWC; /* WhereClause currently being scanned */ 288 char *zCollName; /* Required collating sequence, if not NULL */ 289 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 290 unsigned char nEquiv; /* Number of entries in aEquiv[] */ 291 unsigned char iEquiv; /* Next unused slot in aEquiv[] */ 292 u32 opMask; /* Acceptable operators */ 293 int k; /* Resume scanning at this->pWC->a[this->k] */ 294 int aEquiv[22]; /* Cursor,Column pairs for equivalence classes */ 295 }; 296 297 /* 298 ** An instance of the following structure holds all information about a 299 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 300 ** 301 ** Explanation of pOuter: For a WHERE clause of the form 302 ** 303 ** a AND ((b AND c) OR (d AND e)) AND f 304 ** 305 ** There are separate WhereClause objects for the whole clause and for 306 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 307 ** subclauses points to the WhereClause object for the whole clause. 308 */ 309 struct WhereClause { 310 WhereInfo *pWInfo; /* WHERE clause processing context */ 311 WhereClause *pOuter; /* Outer conjunction */ 312 u8 op; /* Split operator. TK_AND or TK_OR */ 313 int nTerm; /* Number of terms */ 314 int nSlot; /* Number of entries in a[] */ 315 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 316 #if defined(SQLITE_SMALL_STACK) 317 WhereTerm aStatic[1]; /* Initial static space for a[] */ 318 #else 319 WhereTerm aStatic[8]; /* Initial static space for a[] */ 320 #endif 321 }; 322 323 /* 324 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 325 ** a dynamically allocated instance of the following structure. 326 */ 327 struct WhereOrInfo { 328 WhereClause wc; /* Decomposition into subterms */ 329 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 330 }; 331 332 /* 333 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 334 ** a dynamically allocated instance of the following structure. 335 */ 336 struct WhereAndInfo { 337 WhereClause wc; /* The subexpression broken out */ 338 }; 339 340 /* 341 ** An instance of the following structure keeps track of a mapping 342 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 343 ** 344 ** The VDBE cursor numbers are small integers contained in 345 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 346 ** clause, the cursor numbers might not begin with 0 and they might 347 ** contain gaps in the numbering sequence. But we want to make maximum 348 ** use of the bits in our bitmasks. This structure provides a mapping 349 ** from the sparse cursor numbers into consecutive integers beginning 350 ** with 0. 351 ** 352 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 353 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 354 ** 355 ** For example, if the WHERE clause expression used these VDBE 356 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 357 ** would map those cursor numbers into bits 0 through 5. 358 ** 359 ** Note that the mapping is not necessarily ordered. In the example 360 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 361 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 362 ** does not really matter. What is important is that sparse cursor 363 ** numbers all get mapped into bit numbers that begin with 0 and contain 364 ** no gaps. 365 */ 366 struct WhereMaskSet { 367 int n; /* Number of assigned cursor values */ 368 int ix[BMS]; /* Cursor assigned to each bit */ 369 }; 370 371 /* 372 ** Initialize a WhereMaskSet object 373 */ 374 #define initMaskSet(P) (P)->n=0 375 376 /* 377 ** This object is a convenience wrapper holding all information needed 378 ** to construct WhereLoop objects for a particular query. 379 */ 380 struct WhereLoopBuilder { 381 WhereInfo *pWInfo; /* Information about this WHERE */ 382 WhereClause *pWC; /* WHERE clause terms */ 383 ExprList *pOrderBy; /* ORDER BY clause */ 384 WhereLoop *pNew; /* Template WhereLoop */ 385 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 386 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 387 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 388 int nRecValid; /* Number of valid fields currently in pRec */ 389 #endif 390 }; 391 392 /* 393 ** The WHERE clause processing routine has two halves. The 394 ** first part does the start of the WHERE loop and the second 395 ** half does the tail of the WHERE loop. An instance of 396 ** this structure is returned by the first half and passed 397 ** into the second half to give some continuity. 398 ** 399 ** An instance of this object holds the complete state of the query 400 ** planner. 401 */ 402 struct WhereInfo { 403 Parse *pParse; /* Parsing and code generating context */ 404 SrcList *pTabList; /* List of tables in the join */ 405 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 406 ExprList *pResultSet; /* Result set. DISTINCT operates on these */ 407 WhereLoop *pLoops; /* List of all WhereLoop objects */ 408 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 409 LogEst nRowOut; /* Estimated number of output rows */ 410 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 411 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 412 u8 sorted; /* True if really sorted (not just grouped) */ 413 u8 okOnePass; /* Ok to use one-pass algorithm for UPDATE/DELETE */ 414 u8 untestedTerms; /* Not all WHERE terms resolved by outer loop */ 415 u8 eDistinct; /* One of the WHERE_DISTINCT_* values below */ 416 u8 nLevel; /* Number of nested loop */ 417 int iTop; /* The very beginning of the WHERE loop */ 418 int iContinue; /* Jump here to continue with next record */ 419 int iBreak; /* Jump here to break out of the loop */ 420 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 421 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 422 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 423 WhereClause sWC; /* Decomposition of the WHERE clause */ 424 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 425 }; 426 427 /* 428 ** Private interfaces - callable only by other where.c routines. 429 ** 430 ** where.c: 431 */ 432 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 433 WhereTerm *sqlite3WhereFindTerm( 434 WhereClause *pWC, /* The WHERE clause to be searched */ 435 int iCur, /* Cursor number of LHS */ 436 int iColumn, /* Column number of LHS */ 437 Bitmask notReady, /* RHS must not overlap with this mask */ 438 u32 op, /* Mask of WO_xx values describing operator */ 439 Index *pIdx /* Must be compatible with this index, if not NULL */ 440 ); 441 442 /* wherecode.c: */ 443 #ifndef SQLITE_OMIT_EXPLAIN 444 int sqlite3WhereExplainOneScan( 445 Parse *pParse, /* Parse context */ 446 SrcList *pTabList, /* Table list this loop refers to */ 447 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 448 int iLevel, /* Value for "level" column of output */ 449 int iFrom, /* Value for "from" column of output */ 450 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 451 ); 452 #else 453 # define sqlite3WhereExplainOneScan(u,v,w,x,y,z) 0 454 #endif /* SQLITE_OMIT_EXPLAIN */ 455 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 456 void sqlite3WhereAddScanStatus( 457 Vdbe *v, /* Vdbe to add scanstatus entry to */ 458 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 459 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 460 int addrExplain /* Address of OP_Explain (or 0) */ 461 ); 462 #else 463 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 464 #endif 465 Bitmask sqlite3WhereCodeOneLoopStart( 466 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 467 int iLevel, /* Which level of pWInfo->a[] should be coded */ 468 Bitmask notReady /* Which tables are currently available */ 469 ); 470 471 /* whereexpr.c: */ 472 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 473 void sqlite3WhereClauseClear(WhereClause*); 474 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 475 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 476 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 477 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 478 479 480 481 482 483 /* 484 ** Bitmasks for the operators on WhereTerm objects. These are all 485 ** operators that are of interest to the query planner. An 486 ** OR-ed combination of these values can be used when searching for 487 ** particular WhereTerms within a WhereClause. 488 */ 489 #define WO_IN 0x0001 490 #define WO_EQ 0x0002 491 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 492 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 493 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 494 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 495 #define WO_MATCH 0x0040 496 #define WO_IS 0x0080 497 #define WO_ISNULL 0x0100 498 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 499 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 500 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 501 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 502 503 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 504 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 505 506 /* 507 ** These are definitions of bits in the WhereLoop.wsFlags field. 508 ** The particular combination of bits in each WhereLoop help to 509 ** determine the algorithm that WhereLoop represents. 510 */ 511 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 512 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 513 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 514 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 515 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 516 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 517 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 518 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 519 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 520 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 521 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 522 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 523 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 524 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 525 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 526 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 527 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 528 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 529 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 530