sqliteint.h

最新的sqlite3.6.2源代码

#define SQLITE_AFF_MASK     0x67

/*
** Additional bit values that can be ORed with an affinity without
** changing the affinity.
*/
#define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */
#define SQLITE_STOREP2      0x10  /* Store result in reg[P2] rather than jump */

/*
** Each SQL table is represented in memory by an instance of the
** following structure.
**
** Table.zName is the name of the table.  The case of the original
** CREATE TABLE statement is stored, but case is not significant for
** comparisons.
**
** Table.nCol is the number of columns in this table.  Table.aCol is a
** pointer to an array of Column structures, one for each column.
**
** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of
** the column that is that key.   Otherwise Table.iPKey is negative.  Note
** that the datatype of the PRIMARY KEY must be INTEGER for this field to
** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
** is generated for each row of the table.  TF_HasPrimaryKey is set if
** the table has any PRIMARY KEY, INTEGER or otherwise.
**
** Table.tnum is the page number for the root BTree page of the table in the
** database file.  If Table.iDb is the index of the database table backend
** in sqlite.aDb[].  0 is for the main database and 1 is for the file that
** holds temporary tables and indices.  If TF_Ephemeral is set
** then the table is stored in a file that is automatically deleted
** when the VDBE cursor to the table is closed.  In this case Table.tnum 
** refers VDBE cursor number that holds the table open, not to the root
** page number.  Transient tables are used to hold the results of a
** sub-query that appears instead of a real table name in the FROM clause 
** of a SELECT statement.
*/
struct Table {
  sqlite3 *db;         /* Associated database connection.  Might be NULL. */
  char *zName;         /* Name of the table or view */
  int iPKey;           /* If not negative, use aCol[iPKey] as the primary key */
  int nCol;            /* Number of columns in this table */
  Column *aCol;        /* Information about each column */
  Index *pIndex;       /* List of SQL indexes on this table. */
  int tnum;            /* Root BTree node for this table (see note above) */
  Select *pSelect;     /* NULL for tables.  Points to definition if a view. */
  u16 nRef;            /* Number of pointers to this Table */
  u8 tabFlags;         /* Mask of TF_* values */
  u8 keyConf;          /* What to do in case of uniqueness conflict on iPKey */
  Trigger *pTrigger;   /* List of SQL triggers on this table */
  FKey *pFKey;         /* Linked list of all foreign keys in this table */
  char *zColAff;       /* String defining the affinity of each column */
#ifndef SQLITE_OMIT_CHECK
  Expr *pCheck;        /* The AND of all CHECK constraints */
#endif
#ifndef SQLITE_OMIT_ALTERTABLE
  int addColOffset;    /* Offset in CREATE TABLE stmt to add a new column */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Module *pMod;        /* Pointer to the implementation of the module */
  sqlite3_vtab *pVtab; /* Pointer to the module instance */
  int nModuleArg;      /* Number of arguments to the module */
  char **azModuleArg;  /* Text of all module args. [0] is module name */
#endif
  Schema *pSchema;     /* Schema that contains this table */
};

/*
** Allowed values for Tabe.tabFlags.
*/
#define TF_Readonly        0x01    /* Read-only system table */
#define TF_Ephemeral       0x02    /* An emphermal table */
#define TF_HasPrimaryKey   0x04    /* Table has a primary key */
#define TF_Autoincrement   0x08    /* Integer primary key is autoincrement */
#define TF_Virtual         0x10    /* Is a virtual table */
#define TF_NeedMetadata    0x20    /* aCol[].zType and aCol[].pColl missing */



/*
** Test to see whether or not a table is a virtual table.  This is
** done as a macro so that it will be optimized out when virtual
** table support is omitted from the build.
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#  define IsVirtual(X)      (((X)->tabFlags & TF_Virtual)!=0)
#  define IsHiddenColumn(X) ((X)->isHidden)
#else
#  define IsVirtual(X)      0
#  define IsHiddenColumn(X) 0
#endif

/*
** Each foreign key constraint is an instance of the following structure.
**
** A foreign key is associated with two tables.  The "from" table is
** the table that contains the REFERENCES clause that creates the foreign
** key.  The "to" table is the table that is named in the REFERENCES clause.
** Consider this example:
**
**     CREATE TABLE ex1(
**       a INTEGER PRIMARY KEY,
**       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
**     );
**
** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
**
** Each REFERENCES clause generates an instance of the following structure
** which is attached to the from-table.  The to-table need not exist when
** the from-table is created.  The existance of the to-table is not checked
** until an attempt is made to insert data into the from-table.
**
** The sqlite.aFKey hash table stores pointers to this structure
** given the name of a to-table.  For each to-table, all foreign keys
** associated with that table are on a linked list using the FKey.pNextTo
** field.
*/
struct FKey {
  Table *pFrom;     /* The table that constains the REFERENCES clause */
  FKey *pNextFrom;  /* Next foreign key in pFrom */
  char *zTo;        /* Name of table that the key points to */
  FKey *pNextTo;    /* Next foreign key that points to zTo */
  int nCol;         /* Number of columns in this key */
  struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
    int iFrom;         /* Index of column in pFrom */
    char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */
  } *aCol;          /* One entry for each of nCol column s */
  u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
  u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
  u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
  u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
};

/*
** SQLite supports many different ways to resolve a constraint
** error.  ROLLBACK processing means that a constraint violation
** causes the operation in process to fail and for the current transaction
** to be rolled back.  ABORT processing means the operation in process
** fails and any prior changes from that one operation are backed out,
** but the transaction is not rolled back.  FAIL processing means that
** the operation in progress stops and returns an error code.  But prior
** changes due to the same operation are not backed out and no rollback
** occurs.  IGNORE means that the particular row that caused the constraint
** error is not inserted or updated.  Processing continues and no error
** is returned.  REPLACE means that preexisting database rows that caused
** a UNIQUE constraint violation are removed so that the new insert or
** update can proceed.  Processing continues and no error is reported.
**
** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.
** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
** key is set to NULL.  CASCADE means that a DELETE or UPDATE of the
** referenced table row is propagated into the row that holds the
** foreign key.
** 
** The following symbolic values are used to record which type
** of action to take.
*/
#define OE_None     0   /* There is no constraint to check */
#define OE_Rollback 1   /* Fail the operation and rollback the transaction */
#define OE_Abort    2   /* Back out changes but do no rollback transaction */
#define OE_Fail     3   /* Stop the operation but leave all prior changes */
#define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
#define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */

#define OE_Restrict 6   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
#define OE_SetNull  7   /* Set the foreign key value to NULL */
#define OE_SetDflt  8   /* Set the foreign key value to its default */
#define OE_Cascade  9   /* Cascade the changes */

#define OE_Default  99  /* Do whatever the default action is */


/*
** An instance of the following structure is passed as the first
** argument to sqlite3VdbeKeyCompare and is used to control the 
** comparison of the two index keys.
*/
struct KeyInfo {
  sqlite3 *db;        /* The database connection */
  u8 enc;             /* Text encoding - one of the TEXT_Utf* values */
  u16 nField;         /* Number of entries in aColl[] */
  u8 *aSortOrder;     /* If defined an aSortOrder[i] is true, sort DESC */
  CollSeq *aColl[1];  /* Collating sequence for each term of the key */
};

/*
** An instance of the following structure holds information about a
** single index record that has already been parsed out into individual
** values.
**
** A record is an object that contains one or more fields of data.
** Records are used to store the content of a table row and to store
** the key of an index.  A blob encoding of a record is created by
** the OP_MakeRecord opcode of the VDBE and is disassemblied by the
** OP_Column opcode.
**
** This structure holds a record that has already been disassembled
** into its constitutent fields.
*/
struct UnpackedRecord {
  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
  u16 nField;         /* Number of entries in apMem[] */
  u16 flags;          /* Boolean settings.  UNPACKED_... below */
  Mem *aMem;          /* Values */
};

/*
** Allowed values of UnpackedRecord.flags
*/
#define UNPACKED_NEED_FREE     0x0001  /* Memory is from sqlite3Malloc() */
#define UNPACKED_NEED_DESTROY  0x0002  /* apMem[]s should all be destroyed */
#define UNPACKED_IGNORE_ROWID  0x0004  /* Ignore trailing rowid on key1 */
#define UNPACKED_INCRKEY       0x0008  /* Make this key an epsilon larger */
#define UNPACKED_PREFIX_MATCH  0x0010  /* A prefix match is considered OK */

/*
** Each SQL index is represented in memory by an
** instance of the following structure.
**
** The columns of the table that are to be indexed are described
** by the aiColumn[] field of this structure.  For example, suppose
** we have the following table and index:
**
**     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
**     CREATE INDEX Ex2 ON Ex1(c3,c1);
**
** In the Table structure describing Ex1, nCol==3 because there are
** three columns in the table.  In the Index structure describing
** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 
** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
** The second column to be indexed (c1) has an index of 0 in
** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
**
** The Index.onError field determines whether or not the indexed columns
** must be unique and what to do if they are not.  When Index.onError=OE_None,
** it means this is not a unique index.  Otherwise it is a unique index
** and the value of Index.onError indicate the which conflict resolution 
** algorithm to employ whenever an attempt is made to insert a non-unique
** element.
*/
struct Index {
  char *zName;     /* Name of this index */
  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  Schema *pSchema; /* Schema containing this index */
  u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
  char **azColl;   /* Array of collation sequence names for index */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.  Tokens are also used as part of an expression.
**
** Note if Token.z==0 then Token.dyn and Token.n are undefined and
** may contain random values.  Do not make any assuptions about Token.dyn
** and Token.n when Token.z==0.
*/
struct Token {
  const unsigned char *z; /* Text of the token.  Not NULL-terminated! */
  unsigned dyn  : 1;      /* True for malloced memory, false for static */
  unsigned n    : 31;     /* Number of characters in this token */
};

/*
** An instance of this structure contains information needed to generate
** code for a SELECT that contains aggregate functions.
**
** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a
** pointer to this structure.  The Expr.iColumn field is the index in
** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate
** code for that node.
**
** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the
** original Select structure that describes the SELECT statement.  These
** fields do not need to be freed when deallocating the AggInfo structure.
*/
struct AggInfo {
  u8 directMode;          /* Direct rendering mode means take data directly
                          ** from source tables rather than from accumulators */
  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
                          ** than the source table */
  int sortingIdx;         /* Cursor number of the sorting index */
  ExprList *pGroupBy;     /* The group by clause */
  int nSortingColumn;     /* Number of columns in the sorting index */
  struct AggInfo_col {    /* For each column used in source tables */
    Table *pTab;             /* Source table */
    int iTable;              /* Cursor number of the source table */
    int iColumn;             /* Column number within the source table */
    int iSorterColumn;       /* Column number in the sorting index */
    int iMem;                /* Memory location that acts as accumulator */
    Expr *pExpr;             /* The original expression */
  } *aCol;
  int nColumn;            /* Number of used entries in aCol[] */
  int nColumnAlloc;       /* Number of slots allocated for aCol[] */
  int nAccumulator;       /* Number of columns that show through to the output.