diff options
Diffstat (limited to 'src/sqliteInt.h')
| -rw-r--r-- | src/sqliteInt.h | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/src/sqliteInt.h b/src/sqliteInt.h index 3de659f79..7425b2988 100644 --- a/src/sqliteInt.h +++ b/src/sqliteInt.h @@ -2650,23 +2650,28 @@ struct Expr { ** also be used as the argument to a function, in which case the a.zName ** field is not used. ** -** By default the Expr.zSpan field holds a human-readable description of -** the expression that is used in the generation of error messages and -** column labels. In this case, Expr.zSpan is typically the text of a -** column expression as it exists in a SELECT statement. However, if -** the bSpanIsTab flag is set, then zSpan is overloaded to mean the name -** of the result column in the form: DATABASE.TABLE.COLUMN. This later -** form is used for name resolution with nested FROM clauses. +** In order to try to keep memory usage down, the Expr.a.zEName field +** is used for multiple purposes: +** +** bNameIsTab bNameIsSpan Usage +** ---------- ----------- ------------------------- +** false false (1) the AS of result set column +** (2) COLUMN= of an UPDATE +** +** true false DB.TABLE.NAME used to resolve names +** of subqueries +** +** false true Text of the original result set +** expression. */ struct ExprList { int nExpr; /* Number of expressions on the list */ struct ExprList_item { /* For each expression in the list */ Expr *pExpr; /* The parse tree for this expression */ char *zEName; /* Token associated with this expression */ - char *zSpan; /* Original text of the expression */ u8 sortFlags; /* Mask of KEYINFO_ORDER_* flags */ + unsigned eEName :2; /* Meaning of zEName */ unsigned done :1; /* A flag to indicate when processing is finished */ - unsigned bSpanIsTab :1; /* zSpan holds DB.TABLE.COLUMN */ unsigned reusable :1; /* Constant expression is reusable */ unsigned bSorterRef :1; /* Defer evaluation until after sorting */ unsigned bNulls: 1; /* True if explicit "NULLS FIRST/LAST" */ @@ -2681,6 +2686,13 @@ struct ExprList { }; /* +** Allowed values for Expr.a.eEName +*/ +#define ENAME_NAME 0 /* The AS clause of a result set */ +#define ENAME_SPAN 1 /* Complete text of the result set expression */ +#define ENAME_TAB 2 /* "DB.TABLE.NAME" for the result set */ + +/* ** An instance of this structure can hold a simple list of identifiers, ** such as the list "a,b,c" in the following statements: ** |