forked from georgebarwood/Database
-
Notifications
You must be signed in to change notification settings - Fork 0
/
TableExp.cs
358 lines (307 loc) · 10.7 KB
/
TableExp.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
namespace SQLNS {
using G = System.Collections.Generic;
using DBNS;
/* TableExpression is complex as tables arise in different ways:
VALUES table.
Base table ( which may not initially be actually defined and present in the database when parsing a view or function or procedure definition ).
View ( similar to Base table ).
SELECT/SET/FOR expressions ... FROM.
They are also used in different ways:
SELECT to client : SELECT Address FROM dbo.Cust
INSERT source : INSERT INTO dbo.Cust ( Address ) SELECT Address FROM dbo.AddressList
SET source : DECLARE a string SET a = Address FROM dbo.Cust where Id = k
FOR source : DECLARE a string FOR a = Address FROM dbo.Cust
Scalar sub-expression : DECLARE a string SET a = ( SELECT Address FROM dbo.Cust WHERE Id = k )
Rhs of IN expression : SELECT Address FROM dbo.Cust WHERE Id IN ( SELECT id FROM dbo.Cust WHERE Postcode = 'GL1' )
*/
abstract class TableExpression
{
public int ColumnCount; // Number of columns in table
public ColInfo Cols; // Names and types of the columns
public long TableId;
public string Alias;
public virtual DataType Type( int i ){ return Cols.Types[i]; } // Data type of the ith column.
public virtual TableExpression Load( SqlExec e ) { return this; } // Loads table or view definition from database.
public virtual void CheckNames( Exec e ){} // Checks the column names are distinct and not blank.
public virtual void Convert( DataType [] types, Exec e ){} // Converts the expressions ready to be assigned
public virtual void FetchTo( ResultSet rs, EvalEnv ee ){} // Fetchs the table to the specified ResultSet
public virtual G.IEnumerable<bool> GetAll( Value[] row, bool [] used, EvalEnv ee ){ yield return false; } // Iterates through the table.
// Index optimisation.
public virtual IndexFile FindIndex( int colIx ){ return null; }
public virtual bool Get( long id, Value[] row, bool [] used ){ return false; } // Only called if FindIndex is implemented.
// Atomic update.
public virtual void PrepareToCommit() { }
public virtual void Commit() { }
public virtual void Rollback() { }
}
class Select : TableExpression
{
G.List<Exp> Exps;
TableExpression TE;
Exp Where;
OrderByExp[] Order;
bool [] Used;
SortSpec [] SortSpec;
GroupSpec [] GroupSpec;
AggSpec [] AggSpec;
public Select( G.List<Exp> exps, TableExpression te, Exp where, Exp[] group, OrderByExp[] order, bool [] used, SqlExec x )
{
Exps = exps; TE = te; Where = where; Order = order; Used = used;
ColumnCount = exps.Count;
var names = new string[ ColumnCount ];
var types = new DataType[ ColumnCount ];
for ( int i = 0; i < ColumnCount; i += 1 )
{
names[i] = exps[i].Name;
types[i] = exps[i].Type;
}
Cols = new ColInfo( names, types );
if ( x.ParseOnly ) return;
if ( group != null )
{
// Compute AggSpec and GroupSpec
var alist = new G.List<AggSpec>();
for ( int i = 0; i < exps.Count; i += 1 )
{
Exp e = exps[i];
AggOp op = e.GetAggOp();
if ( op != AggOp.None )
{
AggSpec a = new AggSpec();
a.ColIx = i;
a.Type = e.Type;
a.Op = op;
alist.Add( a );
}
}
AggSpec = alist.ToArray();
var glist = new G.List<GroupSpec>();
for ( int i=0; i < group.Length; i += 1 )
{
GroupSpec g = new GroupSpec();
g.ColIx = Exps.Count; // Note: we could look in Exps to see if it is already there rather than adding an extra Exp.
g.Type = group[ i ].Type;
Exps.Add( group[ i ] );
glist.Add( g );
}
GroupSpec = glist.ToArray();
}
if ( Order != null )
{
var sortSpec = new SortSpec[ Order.Length ];
for ( int i = 0; i < Order.Length; i += 1 )
{
// Quite complicated as ORDER BY can use aliases or expressions.
Exp e = Order[i].E;
sortSpec[ i ].Desc = Order[i].Desc;
bool found = false;
if ( e is ExpName )
{
string alias = ((ExpName)e).ColName;
for ( int j = 0; j < Cols.Count; j += 1 )
{
if ( Cols.Names[j] == alias )
{
e = Exps[ j ];
found = true;
break;
}
}
}
int cix = Exps.Count;
Exps.Add( e );
if ( !found ) e.Bind( x );
sortSpec[ i ].Type = e.Type;
sortSpec[ i ].ColIx = cix;
}
SortSpec = sortSpec;
}
}
public override void CheckNames( Exec e )
{
var set = new G.HashSet<string>();
for ( int i = 0; i < Exps.Count; i += 1 )
{
string name = Exps[i].Name;
if ( name == "" ) e.Error( "Unnamed expression: " + Exps[i] );
else if ( set.Contains(name) ) e.Error( "Duplicate name: " + name );
set.Add( name );
}
}
public override void Convert( DataType [] types, Exec e )
{
for ( int i = 0; i < types.Length; i += 1 )
{
DataType assignType = types[ i ];
Exp conv = Exps[i].Convert( assignType );
if ( conv == null ) e.Error( "Assign data type error" );
Exps[i] = conv;
}
}
public override G.IEnumerable<bool> GetAll( Value[] final, bool [] used, EvalEnv e )
{
Value[] tr = new Value[ TE.Cols.Count ];
EvalEnv ee = new EvalEnv( e.Locals, tr, e.ResultSet );
IdSet idSet = Where == null ? null : Where.GetIdSet( TE, ee );
if ( idSet != null ) idSet = new IdCopy( idSet, ee ); // Need to take a copy of the id values if an index is used.
StoredResultSet srs = Order == null ? null : new Sorter( null, SortSpec );
srs = GroupSpec == null ? srs : new Grouper( srs, GroupSpec, AggSpec );
Value [] outrow = srs != null ? new Value[ Exps.Count ] : null;
if ( srs == null )
{
if ( idSet != null )
{
foreach ( long id in idSet.All( ee ) ) if ( TE.Get( id, tr, Used ) )
{
if ( Where == null || ( Where.Eval( ee ).B ) )
{
for ( int i = 0; i < final.Length; i += 1 ) final[ i ] = Exps[ i ].Eval( ee );
yield return true;
}
}
}
else
{
foreach ( bool ok in TE.GetAll( tr, Used, ee ) )
if ( Where == null || ( Where.Eval( ee ).B ) )
{
for ( int i = 0; i < final.Length; i += 1 ) final[ i ] = Exps[ i ].Eval( ee );
yield return true;
}
}
}
else
{
if ( idSet != null )
{
foreach ( long id in idSet.All( ee ) ) if ( TE.Get( id, tr, Used ) )
{
if ( Where == null || Where.Eval( ee ).B )
{
for ( int i = 0; i < Exps.Count; i += 1 ) outrow[ i ] = Exps[ i ].Eval( ee );
srs.NewRow( outrow );
}
}
}
else
{
foreach ( bool ok in TE.GetAll( tr, Used, ee ) )
if ( Where == null || Where.Eval( ee ).B )
{
for ( int i = 0; i < Exps.Count; i += 1 ) outrow[ i ] = Exps[ i ].Eval( ee );
srs.NewRow( outrow );
}
}
foreach( bool b in srs.GetAll( final ) ) yield return true;
}
}
public override void FetchTo( ResultSet rs, EvalEnv e )
{
ResultSet srs = Order == null ? rs : new Sorter( rs, SortSpec );
srs = GroupSpec == null ? srs : new Grouper( srs, GroupSpec, AggSpec );
Value[] tr = new Value[ TE.Cols.Count ];
EvalEnv ee = new EvalEnv( e.Locals, tr, e.ResultSet );
IdSet idSet = Where == null ? null : Where.GetIdSet( TE, ee );
if ( idSet != null ) idSet = new IdCopy( idSet, ee ); // Need to take a copy of the id values if an index is used.
rs.NewTable( Cols );
Value [] outrow = new Value[ Exps.Count ];
if ( idSet != null )
// Fetch subset of source table using id values, send to ResultSet (if it satisfies any WHERE clause )
{
foreach ( long id in idSet.All( ee ) ) if ( TE.Get( id, tr, Used ) )
{
if ( Where == null || Where.Eval( ee ).B )
{
for ( int i = 0; i < Exps.Count; i += 1 ) outrow[ i ] = Exps[ i ].Eval( ee );
if ( !srs.NewRow( outrow ) ) break;
}
}
}
else
// Fetch every record in source table, send it to output ( if it satisfies any WHERE clause )
{
foreach ( bool ok in TE.GetAll( tr, Used, ee ) )
if ( Where == null || Where.Eval( ee ).B )
{
for ( int i = 0; i < Exps.Count; i += 1 ) outrow[ i ] = Exps[ i ].Eval( ee );
if ( !srs.NewRow( outrow ) ) break;
}
}
srs.EndTable();
}
} // end class SelectTableExpression
// ********************************************************************
class ValueTable : TableExpression
{
G.List<Exp[]> Values;
public ValueTable( int n, G.List<Exp[]> values )
{
ColumnCount = n;
Values = values;
}
public override DataType Type( int i )
{
return Values[0][i].Type;
}
bool Convert( int i, DataType t )
{
if ( Type( i ) == t ) return true;
for ( int j = 0; j < Values.Count; j += 1 )
{
Exp conv = Values[ j ][ i ].Convert( t );
if ( conv == null ) return false;
Values[ j ][ i ] = conv;
}
return true;
}
public override void Convert( DataType [] types, Exec e )
{
for ( int i = 0; i < types.Length; i += 1 )
{
if ( !Convert( i, types[ i ] ) )
{
e.Error( "Data type conversion error to " + DTI.Name( types[i] ) );
}
}
}
public override void FetchTo( ResultSet rs, EvalEnv ee )
{
Value [] row = new Value[ ColumnCount ];
for ( int j = 0; j < Values.Count; j += 1 )
{
var e = Values[ j ];
for ( int i=0; i < ColumnCount; i += 1 )
{
row[ i ] = e[ i ].Eval( ee );
}
if ( !rs.NewRow( row ) ) break;
}
}
} // end class ValueTable
// ********************************************************************
class ViewOrTable : TableExpression
{
public string Schema, Name;
public ViewOrTable( string s, string tname )
{
Schema = s;
Name = tname;
}
public override TableExpression Load( SqlExec e )
{
return e.Db.GetTableOrView( Schema, Name, e );
}
} // end class ViewOrTable
// ********************************************************************
class DummyFrom : TableExpression // USed where there is a SELECT with no FROM clause.
{
public DummyFrom()
{
Cols = new ColInfo( new string[0], new DataType[0] );
}
public override G.IEnumerable<bool> GetAll( Value[] row, bool [] used, EvalEnv ee )
{
yield return true;
}
}
} // end namespace SQLNS