Unification of writing. Also, the "mapping" version doesn't copy rows…

… out of the dataframe.

README.md

@@ -140,11 +140,7 @@ df := DataFrame readFromSqliteCursor: (conn execute: 'SELECT * FROM table').
 ```st
 df writeToSqlite: conn tableName: 'table'.
 ```
-#### Write to differently named colums (provide names for ALL DataFrame columns!)
-```st
-df writeToSqlite: conn tableName: 'table' columnNames: #('col1' 'col2' 'col3').
-```
-#### Mapping (selecting / renaming dataframe columns):
+#### Selecting / renaming dataframe columns:
 Let's assume:
 - CREATE TABLE tbl (a,b,c)
 - DataFrame with columns (a,x,c,d)

src/DataFrame-IO-Sqlite/DataFrame.extension.st

@@ -18,7 +18,7 @@ DataFrame >> writeToSqlite: aSqlite3Connection tableName: aString [
 DataFrame >> writeToSqlite: aSqlite3Connection tableName: aString columnMappings: aCollection [
 
 	| writer |
-	writer := DataFrameSqliteColumnMappingWriter 
+	writer := DataFrameSqliteWriter 
 		          writeToTable: aString
 		          columnMappings: aCollection.
 	self writeTo: aSqlite3Connection using: writer
@@ -30,6 +30,6 @@ DataFrame >> writeToSqlite: aSqlite3Connection tableName: aString columnNames: a
 	| writer |
 	writer := DataFrameSqliteWriter
 		          writeToTable: aString
-		          columnNames: aCollection.
+		          columnMappings: aCollection.
 	self writeTo: aSqlite3Connection using: writer
 ]

src/DataFrame-IO-Sqlite/DataFrameSqliteWriter.class.st

@@ -1,58 +1,105 @@
 Class {
 	#name : 'DataFrameSqliteWriter',
-	#superclass : 'DataFrameAbstractSqliteWriter',
+	#superclass : 'DataFrameWriter',
 	#instVars : [
-		'columnNames'
+		'tableName',
+		'columnMappings'
 	],
 	#category : 'DataFrame-IO-Sqlite',
 	#package : 'DataFrame-IO-Sqlite'
 }
 
-{ #category : 'instance creation' }
+{ #category : 'writing' }
 DataFrameSqliteWriter class >> writeToTable: aString [
 
 	^ self new
 		  tableName: aString;
 		  yourself
 ]
 
-{ #category : 'instance creation' }
-DataFrameSqliteWriter class >> writeToTable: aString columnNames: aCollection [
+{ #category : 'writing' }
+DataFrameSqliteWriter class >> writeToTable: aString columnMappings: aCollection [
 
 	^ self new
 		  tableName: aString;
-		  columnNames: aCollection;
+		  columnMappings: aCollection;
 		  yourself
 ]
 
 { #category : 'accessing' }
-DataFrameSqliteWriter >> columnNames [
+DataFrameSqliteWriter >> columnMappings [
 
-	^ columnNames
+	^ columnMappings
 ]
 
 { #category : 'accessing' }
-DataFrameSqliteWriter >> columnNames: anObject [
+DataFrameSqliteWriter >> columnMappings: anObject [
+
+	columnMappings := anObject
+]
+
+{ #category : 'helpers' }
+DataFrameSqliteWriter >> fieldIndicesFor: aDataFrame [
+	"gather indices of columns in dataframe (to avoid lookup by field name later, in loop)"
+
+	^ (self getColumnMappings: aDataFrame) collect: [ :m |
+		  | sourceName |
+		  sourceName := m isAssociation
+			                ifTrue: [ m key ]
+			                ifFalse: [ m ].
+		  aDataFrame columnNames indexOf: sourceName ]
+]
+
+{ #category : 'helpers' }
+DataFrameSqliteWriter >> getColumnMappings: aDataFrame [
+
+	^ columnMappings ifNil: [ aDataFrame columnNames ]
+]
+
+{ #category : 'helpers' }
+DataFrameSqliteWriter >> getColumnNames: aDataFrame [
 
-	columnNames := anObject
+	^ (self getColumnMappings: aDataFrame) collect: [ :m | m value ]
 ]
 
 { #category : 'helpers' }
-DataFrameSqliteWriter >> getColumnNamesFor: aDataFrame [
+DataFrameSqliteWriter >> insertQueryForColumns: aSequence [
+	""
+	^ String streamContents: [ :strm |
+		strm
+			nextPutAll: 'INSERT INTO ';
+			nextPutAll: tableName;
+			nextPut: $(;
+			nextPutAll: (',' join: aSequence);
+			nextPutAll: ')VALUES('.
+		aSequence do: [ :ignore | strm nextPut: $? ] separatedBy: [ strm nextPut: $, ].
+		strm nextPut: $) ]
+]
+
+{ #category : 'accessing' }
+DataFrameSqliteWriter >> tableName [
 
-	columnNames ifNil: [ ^ aDataFrame columnNames ].
-	columnNames size ~= aDataFrame columns size ifTrue: [
-		self error:
-			'Column count mismatch (Writer columns <=> DataFrame columns)' ].
-	^ columnNames
+	^ tableName
+]
+
+{ #category : 'accessing' }
+DataFrameSqliteWriter >> tableName: anObject [
+
+	tableName := anObject
 ]
 
 { #category : 'writing' }
 DataFrameSqliteWriter >> write: aDataFrame to: aSqliteConnection [
 
-	| stmt |
+	| fieldIndices args stmt |
+	fieldIndices := self fieldIndicesFor: aDataFrame.
+	args := Array new: fieldIndices size.
 	stmt := aSqliteConnection prepare:
 		        (self insertQueryForColumns:
-			         (self getColumnNamesFor: aDataFrame)).
-	aDataFrame do: [ :row | stmt execute: row asArray ]
+			         (self getColumnNames: aDataFrame)).
+
+	1 to: aDataFrame dimensions x do: [ :rowIndex |
+		fieldIndices withIndexDo: [ :srcCol :dstCol |
+			args at: dstCol put: (aDataFrame contents at: rowIndex at: srcCol) ].
+		stmt execute: args ]
 ]