diff --git a/CHANGELOG.md b/CHANGELOG.md
index 792ec12..60bc5a1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,10 @@ Types of changes
 - `Fixed` for any bug fixes.
 - `Security` in case of vulnerabilities.
 
+## [0.4.0]
+
+- `Added` `Open` and `Close` methods to column/value reader inferfaces.
+
 ## [0.3.0]
 
 - `Added` moved `min` and `max` to the main metric.
diff --git a/internal/infra/filesReader.go b/internal/infra/filesReader.go
index 9503edd..c0d8245 100644
--- a/internal/infra/filesReader.go
+++ b/internal/infra/filesReader.go
@@ -51,6 +51,9 @@ func NewJSONLFolderReader(folderpath string) (*JSONLFolderReader, error) {
 	}, nil
 }
 
+func (r *JSONLFolderReader) Open() error  { return nil }
+func (r *JSONLFolderReader) Close() error { return nil }
+
 func (r *JSONLFolderReader) BaseName() string {
 	return r.basename
 }
@@ -155,6 +158,9 @@ func NewJSONLColReader(table, column string, decoder *json.Decoder) *JSONLColRea
 	}
 }
 
+func (cr *JSONLColReader) Open() error  { return nil }
+func (cr *JSONLColReader) Close() error { return nil }
+
 func (cr *JSONLColReader) ColName() string {
 	return cr.column
 }
diff --git a/pkg/rimo/driven.go b/pkg/rimo/driven.go
index fb79719..098b5b4 100644
--- a/pkg/rimo/driven.go
+++ b/pkg/rimo/driven.go
@@ -19,7 +19,13 @@ package rimo
 
 import "github.com/cgi-fr/rimo/pkg/model"
 
+type Resource interface {
+	Open() error
+	Close() error
+}
+
 type ColReader interface {
+	Resource
 	ColName() string
 	TableName() string
 	Next() bool
@@ -27,6 +33,7 @@ type ColReader interface {
 }
 
 type Reader interface {
+	Resource
 	BaseName() string
 	Next() bool
 	Col() (ColReader, error)
diff --git a/pkg/rimo/driver.go b/pkg/rimo/driver.go
index 6e28979..98f71ff 100644
--- a/pkg/rimo/driver.go
+++ b/pkg/rimo/driver.go
@@ -32,102 +32,130 @@ type Driver struct {
 	Distinct   bool
 }
 
-//nolint:funlen,cyclop,gocognit
-func (d Driver) AnalyseBase(reader Reader, writer Writer) error {
+func (d Driver) AnalyseBase(reader Reader, writer Writer) (err error) {
+	if err := reader.Open(); err != nil {
+		return fmt.Errorf("failed to open column reader : %w", err)
+	}
+
+	defer func() {
+		if localerr := reader.Close(); err != nil {
+			err = localerr
+		}
+	}()
+
 	baseName := reader.BaseName()
 
 	base := model.NewBase(baseName)
 	tables := map[string]model.Table{}
 
 	for reader.Next() { // itère colonne par colonne
-		valreader, err := reader.Col()
-		if err != nil {
-			return fmt.Errorf("failed to get column reader : %w", err)
+		if err := d.analyse(reader, tables); err != nil {
+			return err
 		}
+	}
 
-		nilcount := 0
+	for _, table := range tables {
+		sort.SliceStable(table.Columns, func(i, j int) bool {
+			return table.Columns[i].Name < table.Columns[j].Name
+		})
 
-		for valreader.Next() {
-			val, err := valreader.Value()
-			if err != nil {
-				return fmt.Errorf("failed to read value : %w", err)
-			}
+		base.Tables = append(base.Tables, table)
+	}
 
-			log.Debug().Msgf("Processing [%s base][%s table][%s column]", baseName, valreader.TableName(), valreader.ColName())
+	sort.SliceStable(base.Tables, func(i, j int) bool {
+		return base.Tables[i].Name < base.Tables[j].Name
+	})
 
-			switch valtyped := val.(type) {
-			case string:
-				col, err := d.AnalyseString(nilcount, valtyped, valreader)
-				if err != nil {
-					return fmt.Errorf("failed to analyse column : %w", err)
-				}
+	err = writer.Export(base)
+	if err != nil {
+		return fmt.Errorf("failed to export base : %w", err)
+	}
 
-				table, exists := tables[valreader.TableName()]
-				if !exists {
-					table = model.Table{
-						Name:    valreader.TableName(),
-						Columns: []model.Column{},
-					}
-				}
+	return nil
+}
 
-				table.Columns = append(table.Columns, col)
+//nolint:funlen,cyclop
+func (d Driver) analyse(reader Reader, tables map[string]model.Table) (err error) {
+	valreader, err := reader.Col()
+	if err != nil {
+		return fmt.Errorf("failed to get column reader : %w", err)
+	}
 
-				tables[valreader.TableName()] = table
-			case float64, float32, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
-				col, err := d.AnalyseNumeric(nilcount, valtyped, valreader)
-				if err != nil {
-					return fmt.Errorf("failed to analyse column : %w", err)
-				}
+	if err := valreader.Open(); err != nil {
+		return fmt.Errorf("failed to open value reader : %w", err)
+	}
 
-				table, exists := tables[valreader.TableName()]
-				if !exists {
-					table = model.Table{
-						Name:    valreader.TableName(),
-						Columns: []model.Column{},
-					}
-				}
+	defer func() {
+		if localerr := reader.Close(); err != nil {
+			err = localerr
+		}
+	}()
 
-				table.Columns = append(table.Columns, col)
+	nilcount := 0
 
-				tables[valreader.TableName()] = table
-			case bool:
-				col, err := d.AnalyseBool(nilcount, valtyped, valreader)
-				if err != nil {
-					return fmt.Errorf("failed to analyse column : %w", err)
-				}
+	for valreader.Next() {
+		val, err := valreader.Value()
+		if err != nil {
+			return fmt.Errorf("failed to read value : %w", err)
+		}
 
-				table, exists := tables[valreader.TableName()]
-				if !exists {
-					table = model.Table{
-						Name:    valreader.TableName(),
-						Columns: []model.Column{},
-					}
+		log.Debug().Msgf("Processing [%s][%s][%s]", reader.BaseName(), valreader.TableName(), valreader.ColName())
+
+		switch valtyped := val.(type) {
+		case string:
+			col, err := d.AnalyseString(nilcount, valtyped, valreader)
+			if err != nil {
+				return fmt.Errorf("failed to analyse column : %w", err)
+			}
+
+			table, exists := tables[valreader.TableName()]
+			if !exists {
+				table = model.Table{
+					Name:    valreader.TableName(),
+					Columns: []model.Column{},
 				}
+			}
 
-				table.Columns = append(table.Columns, col)
+			table.Columns = append(table.Columns, col)
 
-				tables[valreader.TableName()] = table
-			case nil:
-				nilcount++
+			tables[valreader.TableName()] = table
+		case float64, float32, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
+			col, err := d.AnalyseNumeric(nilcount, valtyped, valreader)
+			if err != nil {
+				return fmt.Errorf("failed to analyse column : %w", err)
 			}
-		}
-	}
 
-	for _, table := range tables {
-		sort.SliceStable(table.Columns, func(i, j int) bool {
-			return table.Columns[i].Name < table.Columns[j].Name
-		})
+			table, exists := tables[valreader.TableName()]
+			if !exists {
+				table = model.Table{
+					Name:    valreader.TableName(),
+					Columns: []model.Column{},
+				}
+			}
 
-		base.Tables = append(base.Tables, table)
-	}
+			table.Columns = append(table.Columns, col)
 
-	sort.SliceStable(base.Tables, func(i, j int) bool {
-		return base.Tables[i].Name < base.Tables[j].Name
-	})
+			tables[valreader.TableName()] = table
+		case bool:
+			col, err := d.AnalyseBool(nilcount, valtyped, valreader)
+			if err != nil {
+				return fmt.Errorf("failed to analyse column : %w", err)
+			}
 
-	err := writer.Export(base)
-	if err != nil {
-		return fmt.Errorf("failed to export base : %w", err)
+			table, exists := tables[valreader.TableName()]
+			if !exists {
+				table = model.Table{
+					Name:    valreader.TableName(),
+					Columns: []model.Column{},
+				}
+			}
+
+			table.Columns = append(table.Columns, col)
+
+			tables[valreader.TableName()] = table
+		case nil:
+			nilcount++
+		}
 	}
 
 	return nil
diff --git a/test/suites/testdata/data1/output/data1.yaml b/test/suites/testdata/data1/output/data1.yaml
new file mode 100644
index 0000000..e158360
--- /dev/null
+++ b/test/suites/testdata/data1/output/data1.yaml
@@ -0,0 +1,244 @@
+database: data1
+tables:
+    - name: data_input
+      columns:
+        - name: address
+          type: string
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 0
+            nulls: 0
+            min: 0301 Amy Grove Apt. 325 Janefort, MA 84102
+            max: PSC 4713, Box 9649 APO AA 43433
+            samples:
+                - 0301 Amy Grove Apt. 325 Janefort, MA 84102
+                - 095 Jennifer Turnpike Castrobury, NY 98111
+                - 06210 David Court South Kimberly, IL 10236
+                - 9038 Frye Ramp South Cheryltown, CT 54262
+                - 275 Stone Ridges Suite 885 East Aliciafurt, MH 15407
+          stringMetric:
+            minLen: 31
+            maxLen: 52
+            countLen: 7
+            lengths:
+                - length: 42
+                  freq: 0.3
+                  metrics:
+                    count: 3
+                    empty: 0
+                    nulls: 0
+                    min: 0301 Amy Grove Apt. 325 Janefort, MA 84102
+                    max: 095 Jennifer Turnpike Castrobury, NY 98111
+                    samples:
+                        - 095 Jennifer Turnpike Castrobury, NY 98111
+                        - 06210 David Court South Kimberly, IL 10236
+                        - 0301 Amy Grove Apt. 325 Janefort, MA 84102
+                - length: 41
+                  freq: 0.2
+                  metrics:
+                    count: 2
+                    empty: 0
+                    nulls: 0
+                    min: 536 Robinson Estates Austinside, NV 69535
+                    max: 9038 Frye Ramp South Cheryltown, CT 54262
+                    samples:
+                        - 536 Robinson Estates Austinside, NV 69535
+                        - 9038 Frye Ramp South Cheryltown, CT 54262
+                - length: 37
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: 25545 Cole Court Newtonfurt, KY 13882
+                    max: 25545 Cole Court Newtonfurt, KY 13882
+                    samples:
+                        - 25545 Cole Court Newtonfurt, KY 13882
+                - length: 31
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: PSC 4713, Box 9649 APO AA 43433
+                    max: PSC 4713, Box 9649 APO AA 43433
+                    samples:
+                        - PSC 4713, Box 9649 APO AA 43433
+                - length: 45
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: 2035 Simmons Islands Heatherchester, IN 46152
+                    max: 2035 Simmons Islands Heatherchester, IN 46152
+                    samples:
+                        - 2035 Simmons Islands Heatherchester, IN 46152
+                - length: 52
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: 275 Stone Ridges Suite 885 East Aliciafurt, MH 15407
+                    max: 275 Stone Ridges Suite 885 East Aliciafurt, MH 15407
+                    samples:
+                        - 275 Stone Ridges Suite 885 East Aliciafurt, MH 15407
+                - length: 43
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: 38432 Moreno Turnpike Garrettland, TN 72939
+                    max: 38432 Moreno Turnpike Garrettland, TN 72939
+                    samples:
+                        - 38432 Moreno Turnpike Garrettland, TN 72939
+        - name: age
+          type: numeric
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 0
+            nulls: 0
+            min: 29
+            max: 95
+            samples:
+                - 47
+                - 35
+                - 61
+                - 73
+                - 45
+          numericMetric:
+            mean: 57.7
+        - name: date
+          type: string
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 0
+            nulls: 0
+            min: "2001-08-23"
+            max: "2022-04-23"
+            samples:
+                - "2001-08-23"
+                - "2014-09-09"
+                - "2003-10-11"
+                - "2011-07-13"
+                - "2022-04-23"
+          stringMetric:
+            minLen: 10
+            maxLen: 10
+            countLen: 1
+            lengths:
+                - length: 10
+                  freq: 1
+                  metrics:
+                    count: 10
+                    empty: 0
+                    nulls: 0
+                    min: "2001-08-23"
+                    max: "2022-04-23"
+                    samples:
+                        - "2013-06-11"
+                        - "2011-07-13"
+                        - "2003-10-11"
+                        - "2001-08-23"
+                        - "2010-11-18"
+        - name: phone
+          type: string
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 0
+            nulls: 0
+            min: (330)616-7639x7810
+            max: 828-755-3826
+            samples:
+                - 001-958-985-3039
+                - 001-845-854-2110
+                - "7795418893"
+                - 260-587-0590
+                - 001-533-758-7269
+          stringMetric:
+            minLen: 10
+            maxLen: 21
+            countLen: 6
+            lengths:
+                - length: 16
+                  freq: 0.4
+                  metrics:
+                    count: 4
+                    empty: 0
+                    nulls: 0
+                    min: 001-533-758-7269
+                    max: 001-958-985-3039
+                    samples:
+                        - 001-958-985-3039
+                        - 001-866-271-0116
+                        - 001-845-854-2110
+                        - 001-533-758-7269
+                - length: 12
+                  freq: 0.2
+                  metrics:
+                    count: 2
+                    empty: 0
+                    nulls: 0
+                    min: 260-587-0590
+                    max: 828-755-3826
+                    samples:
+                        - 828-755-3826
+                        - 260-587-0590
+                - length: 13
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: (517)819-3454
+                    max: (517)819-3454
+                    samples:
+                        - (517)819-3454
+                - length: 21
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: +1-407-997-8293x68130
+                    max: +1-407-997-8293x68130
+                    samples:
+                        - +1-407-997-8293x68130
+                - length: 10
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: "7795418893"
+                    max: "7795418893"
+                    samples:
+                        - "7795418893"
+                - length: 18
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 0
+                    nulls: 0
+                    min: (330)616-7639x7810
+                    max: (330)616-7639x7810
+                    samples:
+                        - (330)616-7639x7810
diff --git a/test/suites/testdata/main/output/main.yaml b/test/suites/testdata/main/output/main.yaml
new file mode 100644
index 0000000..a39f0db
--- /dev/null
+++ b/test/suites/testdata/main/output/main.yaml
@@ -0,0 +1,107 @@
+database: main
+tables:
+    - name: data
+      columns:
+        - name: bool
+          type: bool
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 4
+            nulls: 1
+            distinct: 2
+            samples:
+                - false
+                - true
+                - true
+                - false
+                - true
+          boolMetric:
+            trueRatio: 0.5555555555555556
+        - name: numeric
+          type: numeric
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 3
+            nulls: 1
+            distinct: 7
+            min: -235
+            max: 100
+            samples:
+                - -0
+                - 1
+                - 3.1415
+                - -235
+                - 2.12e-06
+          numericMetric:
+            mean: -13.539833097777777
+        - name: string
+          type: string
+          config:
+            concept: ""
+            constraint: []
+            confidential: null
+          mainMetric:
+            count: 10
+            empty: 1
+            nulls: 1
+            distinct: 9
+            min: ""
+            max: 教育漢字
+            samples:
+                - \
+                - 教育漢字
+                - "tabs\t       "
+                - "new\nline    "
+                - 'hello world '
+          stringMetric:
+            minLen: 0
+            maxLen: 12
+            countLen: 3
+            lengths:
+                - length: 12
+                  freq: 0.5
+                  metrics:
+                    count: 5
+                    empty: 0
+                    nulls: 0
+                    distinct: 5
+                    min: 'hello world '
+                    max: 教育漢字
+                    samples:
+                        - "new\nline    "
+                        - 'hello world '
+                        - "tabs\t       "
+                        - 教育漢字
+                        - '€         '
+                - length: 1
+                  freq: 0.3
+                  metrics:
+                    count: 3
+                    empty: 0
+                    nulls: 0
+                    distinct: 3
+                    min: ' '
+                    max: _
+                    samples:
+                        - ' '
+                        - _
+                        - \
+                - length: 0
+                  freq: 0.1
+                  metrics:
+                    count: 1
+                    empty: 1
+                    nulls: 0
+                    distinct: 1
+                    min: ""
+                    max: ""
+                    samples:
+                        - ""