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Parse foreign key constraints and populate internal data structures

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appropriately.  Constraints are still not enforced. (CVS 738)

FossilOrigin-Name: 170711ca65dc894d0486b9d575edb8f1708250fb
This commit is contained in:
drh
2002-08-31 18:53:06 +00:00
parent b680a344e5
commit c2eef3b32b
13 changed files with 527 additions and 174 deletions
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65
src/sqliteInt.h
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@@ -11,7 +11,7 @@
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.144 2002/08/28 03:00:59 drh Exp $
** @(#) $Id: sqliteInt.h,v 1.145 2002/08/31 18:53:07 drh Exp $
*/
#include "sqlite.h"
#include "hash.h"
@@ -175,6 +175,7 @@ typedef struct FuncDef FuncDef;
typedef struct Trigger Trigger;
typedef struct TriggerStep TriggerStep;
typedef struct TriggerStack TriggerStack;
typedef struct FKey FKey;
/*
** Each database is an instance of the following structure.
@@ -206,6 +207,7 @@ struct sqlite {
Hash idxHash; /* All (named) indices indexed by name */
Hash trigHash; /* All triggers indexed by name */
Hash aFunc; /* All functions that can be in SQL exprs */
Hash aFKey; /* Foreign keys indexed by to-table */
int lastRowid; /* ROWID of most recent insert */
int priorNewRowid; /* Last randomly generated ROWID */
int onError; /* Default conflict algorithm */
@@ -330,10 +332,52 @@ struct Table {
u8 hasPrimKey; /* True if there exists a primary key */
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 */
};
/*
** SQLite supports 5 different ways to resolve a contraint
** 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 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 contraint
** 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
@@ -346,6 +390,13 @@ struct Table {
** 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 there symbolic values are used to record which type
** of action to take.
@@ -356,7 +407,13 @@ struct Table {
#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_Default 9 /* Do whatever the default action is */
#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 */
/*
** Each SQL index is represented in memory by an
@@ -947,3 +1004,5 @@ TriggerStep *sqliteTriggerUpdateStep(Token*, ExprList*, Expr*, int);
TriggerStep *sqliteTriggerDeleteStep(Token*, Expr*);
void sqliteDeleteTrigger(Trigger*);
int sqliteJoinType(Parse*, Token*, Token*, Token*);
void sqliteCreateForeignKey(Parse*, IdList*, Token*, IdList*, int);
void sqliteDeferForeignKey(Parse*, int);