feat: export presence

CHANGELOG.md

@@ -19,6 +19,7 @@ Types of changes
 - `Added` possibility to filter columns via `select` property in ingress descriptors
 - `Added` commands `set-parent-select` and `set-child-select` to `lino id`
 - `Added` `import: no` option for columns in `tables.yaml` configuration
+- `Added` `export: presence` option for columns in `tables.yaml` configuration
 
 ## [3.0.2]
 

internal/infra/analyse/sql_datasource.go

@@ -134,7 +134,7 @@ func (ds *SQLDataSource) Open() error {
 	// Get WHERE Clause query
 	sqlWhere, values := commonsql.GetWhereSQLAndValues(map[string]any{}, ds.where, ds.dialect)
 
-	sql := ds.dialect.Select(ds.table, ds.schema, sqlWhere, false, ds.column)
+	sql := ds.dialect.Select(ds.table, ds.schema, sqlWhere, false, commonsql.ColumnExportDefinition{Name: ds.column})
 
 	// If log level is more than debug level, this function will log all SQL Query
 	commonsql.LogSQLQuery(sql, values, ds.dialect)

internal/infra/commonsql/dialect.go

@@ -25,6 +25,19 @@ import (
 	"github.com/rs/zerolog/log"
 )
 
+type ColumnExportDefinition struct {
+	Name         string
+	OnlyPresence bool
+}
+
+func Names(columns []ColumnExportDefinition) []string {
+	us := make([]string, len(columns))
+	for i := range columns {
+		us[i] = columns[i].Name
+	}
+	return us
+}
+
 type Dialect interface {
 	// Placeholder format variable in query
 	Placeholder(int) string
@@ -35,9 +48,9 @@ type Dialect interface {
 	// Where clause
 	Where(string) string
 	// Select clause
-	Select(tableName string, schemaName string, where string, distinct bool, columns ...string) string
+	Select(tableName string, schemaName string, where string, distinct bool, columns ...ColumnExportDefinition) string
 	// SelectLimit clause
-	SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...string) string
+	SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...ColumnExportDefinition) string
 	// Quote identifier
 	Quote(id string) string
 

internal/infra/commonsql/dialect_db2.go

@@ -53,7 +53,7 @@ func (db2 Db2Dialect) Where(where string) string {
 }
 
 // Select clause
-func (db2 Db2Dialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...string) string {
+func (db2 Db2Dialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -62,11 +62,15 @@ func (db2 Db2Dialect) Select(tableName string, schemaName string, where string,
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = db2.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = db2.selectPresence(names[i])
+			} else {
+				names[i] = db2.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -80,7 +84,7 @@ func (db2 Db2Dialect) Select(tableName string, schemaName string, where string,
 }
 
 // SelectLimit clause
-func (db2 Db2Dialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...string) string {
+func (db2 Db2Dialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -89,11 +93,15 @@ func (db2 Db2Dialect) SelectLimit(tableName string, schemaName string, where str
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = db2.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = db2.selectPresence(names[i])
+			} else {
+				names[i] = db2.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -123,3 +131,7 @@ func (db2 Db2Dialect) Quote(id string) string {
 func (db2 Db2Dialect) CreateSelect(sel string, where string, limit string, columns string, from string) string {
 	return fmt.Sprintf("%s %s %s %s %s", sel, columns, from, where, limit)
 }
+
+func (db2 Db2Dialect) selectPresence(column string) string {
+	return fmt.Sprintf("CASE WHEN %s IS NOT NULL THEN 1 ELSE NULL END AS %s", db2.Quote(column), db2.Quote(column))
+}

internal/infra/commonsql/dialect_mariadb.go

@@ -53,7 +53,7 @@ func (pd MariadbDialect) Where(where string) string {
 }
 
 // Select clause
-func (pd MariadbDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...string) string {
+func (pd MariadbDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -62,11 +62,15 @@ func (pd MariadbDialect) Select(tableName string, schemaName string, where strin
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = pd.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = pd.selectPresence(names[i])
+			} else {
+				names[i] = pd.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -80,7 +84,7 @@ func (pd MariadbDialect) Select(tableName string, schemaName string, where strin
 }
 
 // SelectLimit clause
-func (pd MariadbDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...string) string {
+func (pd MariadbDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -89,11 +93,15 @@ func (pd MariadbDialect) SelectLimit(tableName string, schemaName string, where
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = pd.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = pd.selectPresence(names[i])
+			} else {
+				names[i] = pd.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -123,3 +131,7 @@ func (sd MariadbDialect) Quote(id string) string {
 func (sd MariadbDialect) CreateSelect(sel string, where string, limit string, columns string, from string) string {
 	return fmt.Sprintf("%s %s %s %s %s", sel, columns, from, where, limit)
 }
+
+func (sd MariadbDialect) selectPresence(column string) string {
+	return fmt.Sprintf("CASE WHEN %s IS NOT NULL THEN 'TRUE' ELSE NULL END AS %s", sd.Quote(column), sd.Quote(column))
+}

internal/infra/commonsql/dialect_oracle.go

@@ -53,7 +53,7 @@ func (od OracleDialect) Where(where string) string {
 }
 
 // Select clause
-func (od OracleDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...string) string {
+func (od OracleDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -62,11 +62,15 @@ func (od OracleDialect) Select(tableName string, schemaName string, where string
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = od.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = od.selectPresence(names[i])
+			} else {
+				names[i] = od.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -80,7 +84,7 @@ func (od OracleDialect) Select(tableName string, schemaName string, where string
 }
 
 // SelectLimit clause
-func (od OracleDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...string) string {
+func (od OracleDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -89,11 +93,15 @@ func (od OracleDialect) SelectLimit(tableName string, schemaName string, where s
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = od.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = od.selectPresence(names[i])
+			} else {
+				names[i] = od.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -123,3 +131,7 @@ func (od OracleDialect) Quote(id string) string {
 func (od OracleDialect) CreateSelect(sel string, where string, limit string, columns string, from string) string {
 	return fmt.Sprintf("%s %s %s %s %s", sel, columns, from, where, limit)
 }
+
+func (od OracleDialect) selectPresence(column string) string {
+	return fmt.Sprintf("CASE WHEN %s IS NOT NULL THEN 'TRUE' ELSE NULL END AS %s", od.Quote(column), od.Quote(column))
+}

internal/infra/commonsql/dialect_postgres.go

@@ -53,7 +53,7 @@ func (pgd PostgresDialect) Where(where string) string {
 }
 
 // Select clause
-func (pgd PostgresDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...string) string {
+func (pgd PostgresDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -62,11 +62,15 @@ func (pgd PostgresDialect) Select(tableName string, schemaName string, where str
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
+	if names := Names(columns); len(names) > 0 {
 		for i := range columns {
-			columns[i] = pgd.Quote(columns[i])
+			if columns[i].OnlyPresence {
+				names[i] = pgd.selectPresence(names[i])
+			} else {
+				names[i] = pgd.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -80,7 +84,7 @@ func (pgd PostgresDialect) Select(tableName string, schemaName string, where str
 }
 
 // SelectLimit clause
-func (pgd PostgresDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...string) string {
+func (pgd PostgresDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -89,11 +93,15 @@ func (pgd PostgresDialect) SelectLimit(tableName string, schemaName string, wher
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
-		for i := range columns {
-			columns[i] = pgd.Quote(columns[i])
+	if names := Names(columns); len(names) > 0 {
+		for i := range names {
+			if columns[i].OnlyPresence {
+				names[i] = pgd.selectPresence(names[i])
+			} else {
+				names[i] = pgd.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -123,3 +131,7 @@ func (pgd PostgresDialect) Quote(id string) string {
 func (pgd PostgresDialect) CreateSelect(sel string, where string, limit string, columns string, from string) string {
 	return fmt.Sprintf("%s %s %s %s %s", sel, columns, from, where, limit)
 }
+
+func (pgd PostgresDialect) selectPresence(column string) string {
+	return fmt.Sprintf("CASE WHEN (%s IS NOT NULL) THEN TRUE ELSE NULL END AS %s", pgd.Quote(column), pgd.Quote(column))
+}

internal/infra/commonsql/dialect_sqlserver.go

@@ -54,7 +54,7 @@ func (sd SQLServerDialect) Where(where string) string {
 }
 
 // Select clause
-func (sd SQLServerDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...string) string {
+func (sd SQLServerDialect) Select(tableName string, schemaName string, where string, distinct bool, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -63,11 +63,15 @@ func (sd SQLServerDialect) Select(tableName string, schemaName string, where str
 		query.WriteString("DISTINCT ")
 	}
 
-	if len(columns) > 0 {
+	if names := Names(columns); len(names) > 0 {
 		for i := range columns {
-			columns[i] = sd.Quote(columns[i])
+			if columns[i].OnlyPresence {
+				names[i] = sd.selectPresence(names[i])
+			} else {
+				names[i] = sd.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -81,7 +85,7 @@ func (sd SQLServerDialect) Select(tableName string, schemaName string, where str
 }
 
 // SelectLimit clause
-func (sd SQLServerDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...string) string {
+func (sd SQLServerDialect) SelectLimit(tableName string, schemaName string, where string, distinct bool, limit uint, columns ...ColumnExportDefinition) string {
 	var query strings.Builder
 
 	query.WriteString("SELECT ")
@@ -93,11 +97,15 @@ func (sd SQLServerDialect) SelectLimit(tableName string, schemaName string, wher
 	query.WriteString(sd.Limit(limit))
 	query.WriteRune(' ')
 
-	if len(columns) > 0 {
+	if names := Names(columns); len(names) > 0 {
 		for i := range columns {
-			columns[i] = sd.Quote(columns[i])
+			if columns[i].OnlyPresence {
+				names[i] = sd.selectPresence(names[i])
+			} else {
+				names[i] = sd.Quote(names[i])
+			}
 		}
-		query.WriteString(strings.Join(columns, ", "))
+		query.WriteString(strings.Join(names, ", "))
 	} else {
 		query.WriteRune('*')
 	}
@@ -125,3 +133,7 @@ func (sd SQLServerDialect) Quote(id string) string {
 func (sd SQLServerDialect) CreateSelect(sel string, where string, limit string, columns string, from string) string {
 	return fmt.Sprintf("%s %s %s %s %s", sel, limit, columns, from, where)
 }
+
+func (sd SQLServerDialect) selectPresence(column string) string {
+	return fmt.Sprintf("CASE WHEN %s IS NOT NULL THEN 1 ELSE NULL END AS %s", sd.Quote(column), sd.Quote(column))
+}