diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/encode.c | 4 | ||||
| -rw-r--r-- | src/main.c | 9 | ||||
| -rw-r--r-- | src/printf.c | 4 | ||||
| -rw-r--r-- | src/select.c | 96 | ||||
| -rw-r--r-- | src/vdbe.c | 6 |
5 files changed, 92 insertions, 27 deletions
diff --git a/src/encode.c b/src/encode.c index 523a4db11..a4bea5574 100644 --- a/src/encode.c +++ b/src/encode.c @@ -12,10 +12,10 @@ ** This file contains helper routines used to translate binary data into ** a null-terminated string (suitable for use in SQLite) and back again. ** These are convenience routines for use by people who want to store binary -** data in an SQLite database. The code in this file is used by any other +** data in an SQLite database. The code in this file is not used by any other ** part of the SQLite library. ** -** $Id: encode.c,v 1.4 2003/01/11 14:25:40 drh Exp $ +** $Id: encode.c,v 1.5 2003/01/19 03:59:46 drh Exp $ */ #include <string.h> diff --git a/src/main.c b/src/main.c index 48956db7a..23efd5546 100644 --- a/src/main.c +++ b/src/main.c @@ -14,7 +14,7 @@ ** other files are for internal use by SQLite and should not be ** accessed by users of the library. ** -** $Id: main.c,v 1.108 2003/01/18 17:04:09 drh Exp $ +** $Id: main.c,v 1.109 2003/01/19 03:59:47 drh Exp $ */ #include "sqliteInt.h" #include "os.h" @@ -39,7 +39,7 @@ typedef struct { ** argv[0] = "file-format" or "schema-cookie" or "table" or "index" ** argv[1] = table or index name or meta statement type. ** argv[2] = root page number for table or index. NULL for meta. -** argv[3] = SQL create statement for the table or index +** argv[3] = SQL text for a CREATE TABLE or CREATE INDEX statement. ** argv[4] = "1" for temporary files, "0" for main database ** */ @@ -391,7 +391,7 @@ sqlite *sqlite_open(const char *zFilename, int mode, char **pzErrMsg){ /* If the database is in formats 1 or 2, then upgrade it to ** version 3. This will reconstruct all indices. If the ** upgrade fails for any reason (ex: out of disk space, database - ** is read only, interrupt receive, etc.) then refuse to open. + ** is read only, interrupt received, etc.) then refuse to open. */ if( rc==SQLITE_OK && db->file_format<3 ){ char *zErr = 0; @@ -786,7 +786,8 @@ void sqlite_freemem(void *p){ free(p); } /* ** Windows systems need functions to call to return the sqlite_version -** and sqlite_encoding strings. +** and sqlite_encoding strings since they are unable to access constants +** within DLLs. */ const char *sqlite_libversion(void){ return sqlite_version; } const char *sqlite_libencoding(void){ return sqlite_encoding; } diff --git a/src/printf.c b/src/printf.c index af703f3f9..1ef6f42ce 100644 --- a/src/printf.c +++ b/src/printf.c @@ -3,8 +3,8 @@ ** the public domain. The original comments are included here for ** completeness. They are slightly out-of-date. ** -** The following modules is an enhanced replacement for the "printf" programs -** found in the standard library. The following enhancements are +** The following modules is an enhanced replacement for the "printf" subroutines +** found in the standard C library. The following enhancements are ** supported: ** ** + Additional functions. The standard set of "printf" functions diff --git a/src/select.c b/src/select.c index 5a72a1a44..29b1f9e3a 100644 --- a/src/select.c +++ b/src/select.c @@ -12,7 +12,7 @@ ** This file contains C code routines that are called by the parser ** to handle SELECT statements in SQLite. ** -** $Id: select.c,v 1.122 2003/01/18 20:11:07 drh Exp $ +** $Id: select.c,v 1.123 2003/01/19 03:59:47 drh Exp $ */ #include "sqliteInt.h" @@ -180,7 +180,7 @@ static void addWhereTerm( /* ** Set the EP_FromJoin property on all terms of the given expression. ** -** The EP_FromJoin property is used at on terms of an expression to tell +** The EP_FromJoin property is used on terms of an expression to tell ** the LEFT OUTER JOIN processing logic that this term is part of the ** join restriction specified in the ON or USING clause and not a part ** of the more general WHERE clause. These terms are moved over to the @@ -677,6 +677,17 @@ static void generateSortTail( /* ** Generate code that will tell the VDBE the datatypes of ** columns in the result set. +** +** This routine only generates code if the "PRAGMA show_datatypes=on" +** has been executed. The datatypes are reported out in the azCol +** parameter to the callback function. The first N azCol[] entries +** are the names of the columns, and the second N entries are the +** datatypes for the columns. +** +** The "datatype" for a result that is a column of a type is the +** datatype definition extracted from the CREATE TABLE statement. +** The datatype for an expression is either TEXT or NUMERIC. The +** datatype for a ROWID field is INTEGER. */ static void generateColumnTypes( Parse *pParse, /* Parser context */ @@ -1187,7 +1198,19 @@ Vdbe *sqliteGetVdbe(Parse *pParse){ ** ** Examples: ** -** SELECT a,b +** CREATE TABLE one(a INTEGER, b TEXT); +** CREATE TABLE two(c VARCHAR(5), d FLOAT); +** +** SELECT b, b FROM one UNION SELECT d, c FROM two ORDER BY 1, 2; +** +** The primary sort key will use SQLITE_SO_NUM because the "d" in +** the second SELECT is numeric. The 1st column of the first SELECT +** is text but that does not matter because a numeric always overrides +** a text. +** +** The secondary key will use the SQLITE_SO_TEXT sort order because +** both the (second) "b" in the first SELECT and the "c" in the second +** SELECT have a datatype of text. */ static void multiSelectSortOrder(Select *p, ExprList *pOrderBy){ int i; @@ -1215,8 +1238,31 @@ static void multiSelectSortOrder(Select *p, ExprList *pOrderBy){ ** This routine is called to process a query that is really the union ** or intersection of two or more separate queries. ** -** "p" points to the right-most of the two queries. The results should -** be stored in eDest with parameter iParm. +** "p" points to the right-most of the two queries. the query on the +** left is p->pPrior. The left query could also be a compound query +** in which case this routine will be called recursively. +** +** The results of the total query are to be written into a destination +** of type eDest with parameter iParm. +** +** Example 1: Consider a three-way compound SQL statement. +** +** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3 +** +** This statement is parsed up as follows: +** +** SELECT c FROM t3 +** | +** `-----> SELECT b FROM t2 +** | +** `------> SELECT c FROM t1 +** +** The arrows in the diagram above represent the Select.pPrior pointer. +** So if this routine is called with p equal to the t3 query, then +** pPrior will be the t2 query. p->op will be TK_UNION in this case. +** +** Notice that because of the way SQLite parses compound SELECTs, the +** individual selects always group from left to right. */ static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){ int rc; /* Success code from a subroutine */ @@ -1695,7 +1741,7 @@ static int flattenSubquery( ** Analyze the SELECT statement passed in as an argument to see if it ** is a simple min() or max() query. If it is and this query can be ** satisfied using a single seek to the beginning or end of an index, -** then generate the code for this SELECT return 1. If this is not a +** then generate the code for this SELECT and return 1. If this is not a ** simple min() or max() query, then return 0; ** ** A simply min() or max() query looks like this: @@ -1826,6 +1872,10 @@ static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){ ** ** SRT_Table Store results in temporary table iParm ** +** The table above is incomplete. Additional eDist value have be added +** since this comment was written. See the selectInnerLoop() function for +** a complete listing of the allowed values of eDest and their meanings. +** ** This routine returns the number of errors. If any errors are ** encountered, then an appropriate error message is left in ** pParse->zErrMsg. @@ -1839,12 +1889,26 @@ static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){ ** change the parent query from a non-aggregate to an aggregate query. ** For that reason, the pParentAgg flag is passed as a pointer, so it ** can be changed. +** +** Example 1: The meaning of the pParent parameter. +** +** SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3; +** \ \_______ subquery _______/ / +** \ / +** \____________________ outer query ___________________/ +** +** This routine is called for the outer query first. For that call, +** pParent will be NULL. During the processing of the outer query, this +** routine is called recursively to handle the subquery. For the recursive +** call, pParent will point to the outer query. Because the subquery is +** the second element in a three-way join, the parentTab parameter will +** be 1 (the 2nd value of a 0-indexed array.) */ int sqliteSelect( Parse *pParse, /* The parser context */ Select *p, /* The SELECT statement being coded. */ - int eDest, /* One of: SRT_Callback Mem Set Union Except */ - int iParm, /* Save result in this memory location, if >=0 */ + int eDest, /* How to dispose of the results */ + int iParm, /* A parameter used by the eDest disposal method */ Select *pParent, /* Another SELECT for which this is a sub-query */ int parentTab, /* Index in pParent->pSrc of this query */ int *pParentAgg /* True if pParent uses aggregate functions */ @@ -1895,9 +1959,9 @@ int sqliteSelect( */ if( pParse->nErr>0 ) goto select_end; - /* Look up every table in the table list and create an appropriate - ** columnlist in pEList if there isn't one already. (The parser leaves - ** a NULL in the p->pEList if the SQL said "SELECT * FROM ...") + /* Expand any "*" terms in the result set. (For example the "*" in + ** "SELECT * FROM t1") The fillInColumnlist() routine also does some + ** other housekeeping - see the header comment for details. */ if( fillInColumnList(pParse, p) ){ goto select_end; @@ -2024,8 +2088,8 @@ int sqliteSelect( v = sqliteGetVdbe(pParse); if( v==0 ) goto select_end; - /* Identify column names if we will be using in the callback. This - ** step is skipped if the output is going to a table or a memory cell. + /* Identify column names if we will be using them in a callback. This + ** step is skipped if the output is going to some other destination. */ if( eDest==SRT_Callback ){ generateColumnNames(pParse, p->base, pTabList, pEList); @@ -2076,8 +2140,9 @@ int sqliteSelect( return rc; } - /* Identify column types if we will be using in the callback. This - ** step is skipped if the output is going to a table or a memory cell. + /* Identify column types if we will be using a callback. This + ** step is skipped if the output is going to a destination other + ** than a callback. */ if( eDest==SRT_Callback ){ generateColumnTypes(pParse, p->base, pTabList, pEList); @@ -2254,7 +2319,6 @@ int sqliteSelect( ** successful coding of the SELECT. */ select_end: - /* pParse->nTab = base; */ sqliteAggregateInfoReset(pParse); return rc; } diff --git a/src/vdbe.c b/src/vdbe.c index ba3fcca82..ac92fa044 100644 --- a/src/vdbe.c +++ b/src/vdbe.c @@ -36,7 +36,7 @@ ** in this file for details. If in doubt, do not deviate from existing ** commenting and indentation practices when changing or adding code. ** -** $Id: vdbe.c,v 1.198 2003/01/16 13:42:43 drh Exp $ +** $Id: vdbe.c,v 1.199 2003/01/19 03:59:47 drh Exp $ */ #include "sqliteInt.h" #include <ctype.h> @@ -1759,8 +1759,8 @@ case OP_Callback: { ** ** Invoke the callback function once with the 2nd argument (the ** number of columns) equal to P1 and with the 4th argument (the -** names of the columns) set according to prior OP_ColumnName and -** OP_ColumnCount instructions. This is all like the regular +** names of the columns) set according to prior OP_ColumnName +** instructions. This is all like the regular ** OP_Callback or OP_SortCallback opcodes. But the 3rd argument ** which normally contains a pointer to an array of pointers to ** data is NULL. |