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 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS 73 int iLikeRepCntr; /* LIKE range processing counter register */ 74 int addrLikeRep; /* LIKE range processing address */ 75 #endif 76 u8 iFrom; /* Which entry in the FROM clause */ 77 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 78 int p1, p2; /* Operands of the opcode used to ends the loop */ 79 union { /* Information that depends on pWLoop->wsFlags */ 80 struct { 81 int nIn; /* Number of entries in aInLoop[] */ 82 struct InLoop { 83 int iCur; /* The VDBE cursor used by this IN operator */ 84 int addrInTop; /* Top of the IN loop */ 85 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 86 } *aInLoop; /* Information about each nested IN operator */ 87 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 88 Index *pCovidx; /* Possible covering index for WHERE_MULTI_OR */ 89 } u; 90 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 91 Bitmask notReady; /* FROM entries not usable at this level */ 92 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 93 int addrVisit; /* Address at which row is visited */ 94 #endif 95 }; 96 97 /* 98 ** Each instance of this object represents an algorithm for evaluating one 99 ** term of a join. Every term of the FROM clause will have at least 100 ** one corresponding WhereLoop object (unless INDEXED BY constraints 101 ** prevent a query solution - which is an error) and many terms of the 102 ** FROM clause will have multiple WhereLoop objects, each describing a 103 ** potential way of implementing that FROM-clause term, together with 104 ** dependencies and cost estimates for using the chosen algorithm. 105 ** 106 ** Query planning consists of building up a collection of these WhereLoop 107 ** objects, then computing a particular sequence of WhereLoop objects, with 108 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 109 ** and that minimize the overall cost. 110 */ 111 struct WhereLoop { 112 Bitmask prereq; /* Bitmask of other loops that must run first */ 113 Bitmask maskSelf; /* Bitmask identifying table iTab */ 114 #ifdef SQLITE_DEBUG 115 char cId; /* Symbolic ID of this loop for debugging use */ 116 #endif 117 u8 iTab; /* Position in FROM clause of table for this loop */ 118 u8 iSortIdx; /* Sorting index number. 0==None */ 119 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 120 LogEst rRun; /* Cost of running each loop */ 121 LogEst nOut; /* Estimated number of output rows */ 122 union { 123 struct { /* Information for internal btree tables */ 124 u16 nEq; /* Number of equality constraints */ 125 Index *pIndex; /* Index used, or NULL */ 126 } btree; 127 struct { /* Information for virtual tables */ 128 int idxNum; /* Index number */ 129 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ 130 i8 isOrdered; /* True if satisfies ORDER BY */ 131 u16 omitMask; /* Terms that may be omitted */ 132 char *idxStr; /* Index identifier string */ 133 } vtab; 134 } u; 135 u32 wsFlags; /* WHERE_* flags describing the plan */ 136 u16 nLTerm; /* Number of entries in aLTerm[] */ 137 u16 nSkip; /* Number of NULL aLTerm[] entries */ 138 /**** whereLoopXfer() copies fields above ***********************/ 139 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 140 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 141 WhereTerm **aLTerm; /* WhereTerms used */ 142 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 143 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 144 }; 145 146 /* This object holds the prerequisites and the cost of running a 147 ** subquery on one operand of an OR operator in the WHERE clause. 148 ** See WhereOrSet for additional information 149 */ 150 struct WhereOrCost { 151 Bitmask prereq; /* Prerequisites */ 152 LogEst rRun; /* Cost of running this subquery */ 153 LogEst nOut; /* Number of outputs for this subquery */ 154 }; 155 156 /* The WhereOrSet object holds a set of possible WhereOrCosts that 157 ** correspond to the subquery(s) of OR-clause processing. Only the 158 ** best N_OR_COST elements are retained. 159 */ 160 #define N_OR_COST 3 161 struct WhereOrSet { 162 u16 n; /* Number of valid a[] entries */ 163 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 164 }; 165 166 /* 167 ** Each instance of this object holds a sequence of WhereLoop objects 168 ** that implement some or all of a query plan. 169 ** 170 ** Think of each WhereLoop object as a node in a graph with arcs 171 ** showing dependencies and costs for travelling between nodes. (That is 172 ** not a completely accurate description because WhereLoop costs are a 173 ** vector, not a scalar, and because dependencies are many-to-one, not 174 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 175 ** Then a WherePath object is a path through the graph that visits some 176 ** or all of the WhereLoop objects once. 177 ** 178 ** The "solver" works by creating the N best WherePath objects of length 179 ** 1. Then using those as a basis to compute the N best WherePath objects 180 ** of length 2. And so forth until the length of WherePaths equals the 181 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 182 ** at the end is the chosen query plan. 183 */ 184 struct WherePath { 185 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 186 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 187 LogEst nRow; /* Estimated number of rows generated by this path */ 188 LogEst rCost; /* Total cost of this path */ 189 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 190 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 191 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 192 }; 193 194 /* 195 ** The query generator uses an array of instances of this structure to 196 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 197 ** clause subexpression is separated from the others by AND operators, 198 ** usually, or sometimes subexpressions separated by OR. 199 ** 200 ** All WhereTerms are collected into a single WhereClause structure. 201 ** The following identity holds: 202 ** 203 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 204 ** 205 ** When a term is of the form: 206 ** 207 ** X <op> <expr> 208 ** 209 ** where X is a column name and <op> is one of certain operators, 210 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 211 ** cursor number and column number for X. WhereTerm.eOperator records 212 ** the <op> using a bitmask encoding defined by WO_xxx below. The 213 ** use of a bitmask encoding for the operator allows us to search 214 ** quickly for terms that match any of several different operators. 215 ** 216 ** A WhereTerm might also be two or more subterms connected by OR: 217 ** 218 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 219 ** 220 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 221 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 222 ** is collected about the OR clause. 223 ** 224 ** If a term in the WHERE clause does not match either of the two previous 225 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 226 ** to the original subexpression content and wtFlags is set up appropriately 227 ** but no other fields in the WhereTerm object are meaningful. 228 ** 229 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 230 ** but they do so indirectly. A single WhereMaskSet structure translates 231 ** cursor number into bits and the translated bit is stored in the prereq 232 ** fields. The translation is used in order to maximize the number of 233 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 234 ** spread out over the non-negative integers. For example, the cursor 235 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 236 ** translates these sparse cursor numbers into consecutive integers 237 ** beginning with 0 in order to make the best possible use of the available 238 ** bits in the Bitmask. So, in the example above, the cursor numbers 239 ** would be mapped into integers 0 through 7. 240 ** 241 ** The number of terms in a join is limited by the number of bits 242 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 243 ** is only able to process joins with 64 or fewer tables. 244 */ 245 struct WhereTerm { 246 Expr *pExpr; /* Pointer to the subexpression that is this term */ 247 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 248 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 249 union { 250 int leftColumn; /* Column number of X in "X <op> <expr>" */ 251 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 252 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 253 } u; 254 LogEst truthProb; /* Probability of truth for this expression */ 255 u16 eOperator; /* A WO_xx value describing <op> */ 256 u16 wtFlags; /* TERM_xxx bit flags. See below */ 257 u8 nChild; /* Number of children that must disable us */ 258 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 259 WhereClause *pWC; /* The clause this term is part of */ 260 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 261 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 262 }; 263 264 /* 265 ** Allowed values of WhereTerm.wtFlags 266 */ 267 #define TERM_DYNAMIC 0x01 /* Need to call sqlite3ExprDelete(db, pExpr) */ 268 #define TERM_VIRTUAL 0x02 /* Added by the optimizer. Do not code */ 269 #define TERM_CODED 0x04 /* This term is already coded */ 270 #define TERM_COPIED 0x08 /* Has a child */ 271 #define TERM_ORINFO 0x10 /* Need to free the WhereTerm.u.pOrInfo object */ 272 #define TERM_ANDINFO 0x20 /* Need to free the WhereTerm.u.pAndInfo obj */ 273 #define TERM_OR_OK 0x40 /* Used during OR-clause processing */ 274 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 275 # define TERM_VNULL 0x80 /* Manufactured x>NULL or x<=NULL term */ 276 #else 277 # define TERM_VNULL 0x00 /* Disabled if not using stat3 */ 278 #endif 279 #define TERM_LIKEOPT 0x100 /* Virtual terms from the LIKE optimization */ 280 #define TERM_LIKECOND 0x200 /* Conditionally this LIKE operator term */ 281 #define TERM_LIKE 0x400 /* The original LIKE operator */ 282 #define TERM_IS 0x800 /* Term.pExpr is an IS operator */ 283 284 /* 285 ** An instance of the WhereScan object is used as an iterator for locating 286 ** terms in the WHERE clause that are useful to the query planner. 287 */ 288 struct WhereScan { 289 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 290 WhereClause *pWC; /* WhereClause currently being scanned */ 291 const char *zCollName; /* Required collating sequence, if not NULL */ 292 Expr *pIdxExpr; /* Search for this index expression */ 293 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 294 unsigned char nEquiv; /* Number of entries in aEquiv[] */ 295 unsigned char iEquiv; /* Next unused slot in aEquiv[] */ 296 u32 opMask; /* Acceptable operators */ 297 int k; /* Resume scanning at this->pWC->a[this->k] */ 298 int aiCur[11]; /* Cursors in the equivalence class */ 299 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 300 }; 301 302 /* 303 ** An instance of the following structure holds all information about a 304 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 305 ** 306 ** Explanation of pOuter: For a WHERE clause of the form 307 ** 308 ** a AND ((b AND c) OR (d AND e)) AND f 309 ** 310 ** There are separate WhereClause objects for the whole clause and for 311 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 312 ** subclauses points to the WhereClause object for the whole clause. 313 */ 314 struct WhereClause { 315 WhereInfo *pWInfo; /* WHERE clause processing context */ 316 WhereClause *pOuter; /* Outer conjunction */ 317 u8 op; /* Split operator. TK_AND or TK_OR */ 318 int nTerm; /* Number of terms */ 319 int nSlot; /* Number of entries in a[] */ 320 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 321 #if defined(SQLITE_SMALL_STACK) 322 WhereTerm aStatic[1]; /* Initial static space for a[] */ 323 #else 324 WhereTerm aStatic[8]; /* Initial static space for a[] */ 325 #endif 326 }; 327 328 /* 329 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 330 ** a dynamically allocated instance of the following structure. 331 */ 332 struct WhereOrInfo { 333 WhereClause wc; /* Decomposition into subterms */ 334 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 335 }; 336 337 /* 338 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 339 ** a dynamically allocated instance of the following structure. 340 */ 341 struct WhereAndInfo { 342 WhereClause wc; /* The subexpression broken out */ 343 }; 344 345 /* 346 ** An instance of the following structure keeps track of a mapping 347 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 348 ** 349 ** The VDBE cursor numbers are small integers contained in 350 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 351 ** clause, the cursor numbers might not begin with 0 and they might 352 ** contain gaps in the numbering sequence. But we want to make maximum 353 ** use of the bits in our bitmasks. This structure provides a mapping 354 ** from the sparse cursor numbers into consecutive integers beginning 355 ** with 0. 356 ** 357 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 358 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 359 ** 360 ** For example, if the WHERE clause expression used these VDBE 361 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 362 ** would map those cursor numbers into bits 0 through 5. 363 ** 364 ** Note that the mapping is not necessarily ordered. In the example 365 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 366 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 367 ** does not really matter. What is important is that sparse cursor 368 ** numbers all get mapped into bit numbers that begin with 0 and contain 369 ** no gaps. 370 */ 371 struct WhereMaskSet { 372 int n; /* Number of assigned cursor values */ 373 int ix[BMS]; /* Cursor assigned to each bit */ 374 }; 375 376 /* 377 ** Initialize a WhereMaskSet object 378 */ 379 #define initMaskSet(P) (P)->n=0 380 381 /* 382 ** This object is a convenience wrapper holding all information needed 383 ** to construct WhereLoop objects for a particular query. 384 */ 385 struct WhereLoopBuilder { 386 WhereInfo *pWInfo; /* Information about this WHERE */ 387 WhereClause *pWC; /* WHERE clause terms */ 388 ExprList *pOrderBy; /* ORDER BY clause */ 389 WhereLoop *pNew; /* Template WhereLoop */ 390 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 391 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 392 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 393 int nRecValid; /* Number of valid fields currently in pRec */ 394 #endif 395 }; 396 397 /* 398 ** The WHERE clause processing routine has two halves. The 399 ** first part does the start of the WHERE loop and the second 400 ** half does the tail of the WHERE loop. An instance of 401 ** this structure is returned by the first half and passed 402 ** into the second half to give some continuity. 403 ** 404 ** An instance of this object holds the complete state of the query 405 ** planner. 406 */ 407 struct WhereInfo { 408 Parse *pParse; /* Parsing and code generating context */ 409 SrcList *pTabList; /* List of tables in the join */ 410 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 411 ExprList *pResultSet; /* Result set. DISTINCT operates on these */ 412 WhereLoop *pLoops; /* List of all WhereLoop objects */ 413 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 414 LogEst nRowOut; /* Estimated number of output rows */ 415 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 416 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 417 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 418 u8 sorted; /* True if really sorted (not just grouped) */ 419 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 420 u8 untestedTerms; /* Not all WHERE terms resolved by outer loop */ 421 u8 eDistinct; /* One of the WHERE_DISTINCT_* values below */ 422 u8 nLevel; /* Number of nested loop */ 423 int iTop; /* The very beginning of the WHERE loop */ 424 int iContinue; /* Jump here to continue with next record */ 425 int iBreak; /* Jump here to break out of the loop */ 426 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 427 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 428 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 429 WhereClause sWC; /* Decomposition of the WHERE clause */ 430 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 431 }; 432 433 /* 434 ** Private interfaces - callable only by other where.c routines. 435 ** 436 ** where.c: 437 */ 438 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 439 WhereTerm *sqlite3WhereFindTerm( 440 WhereClause *pWC, /* The WHERE clause to be searched */ 441 int iCur, /* Cursor number of LHS */ 442 int iColumn, /* Column number of LHS */ 443 Bitmask notReady, /* RHS must not overlap with this mask */ 444 u32 op, /* Mask of WO_xx values describing operator */ 445 Index *pIdx /* Must be compatible with this index, if not NULL */ 446 ); 447 448 /* wherecode.c: */ 449 #ifndef SQLITE_OMIT_EXPLAIN 450 int sqlite3WhereExplainOneScan( 451 Parse *pParse, /* Parse context */ 452 SrcList *pTabList, /* Table list this loop refers to */ 453 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 454 int iLevel, /* Value for "level" column of output */ 455 int iFrom, /* Value for "from" column of output */ 456 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 457 ); 458 #else 459 # define sqlite3WhereExplainOneScan(u,v,w,x,y,z) 0 460 #endif /* SQLITE_OMIT_EXPLAIN */ 461 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 462 void sqlite3WhereAddScanStatus( 463 Vdbe *v, /* Vdbe to add scanstatus entry to */ 464 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 465 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 466 int addrExplain /* Address of OP_Explain (or 0) */ 467 ); 468 #else 469 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 470 #endif 471 Bitmask sqlite3WhereCodeOneLoopStart( 472 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 473 int iLevel, /* Which level of pWInfo->a[] should be coded */ 474 Bitmask notReady /* Which tables are currently available */ 475 ); 476 477 /* whereexpr.c: */ 478 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 479 void sqlite3WhereClauseClear(WhereClause*); 480 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 481 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 482 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 483 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 484 void sqlite3WhereTabFuncArgs(Parse*, struct SrcList_item*, WhereClause*); 485 486 487 488 489 490 /* 491 ** Bitmasks for the operators on WhereTerm objects. These are all 492 ** operators that are of interest to the query planner. An 493 ** OR-ed combination of these values can be used when searching for 494 ** particular WhereTerms within a WhereClause. 495 */ 496 #define WO_IN 0x0001 497 #define WO_EQ 0x0002 498 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 499 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 500 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 501 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 502 #define WO_MATCH 0x0040 503 #define WO_IS 0x0080 504 #define WO_ISNULL 0x0100 505 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 506 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 507 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 508 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 509 510 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 511 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 512 513 /* 514 ** These are definitions of bits in the WhereLoop.wsFlags field. 515 ** The particular combination of bits in each WhereLoop help to 516 ** determine the algorithm that WhereLoop represents. 517 */ 518 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 519 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 520 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 521 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 522 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 523 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 524 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 525 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 526 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 527 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 528 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 529 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 530 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 531 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 532 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 533 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 534 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 535 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 536 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 537