feat(postgresql): Add support for PostgreSQL multi-dimensional arrays (#2338)

This PR adds support for generating model fields from multi-dimensional postgresql array columns. The approach here is to pass around an additional column attribute array_bounds representing the dimensions of the postgres array column. When generating code, the array_bounds is checked along is_array to determine the dimensions of the resulting struct field. Would be happy to hear alternative approaches or solutions here as well.

https://www.postgresql.org/docs/14/arrays.html

Fixes issue: #1494
Replaces #1651 #2308 #2309

Author: colli173

internal/cmd/shim.go

@@ -169,11 +169,12 @@ func pluginCatalog(c *catalog.Catalog) *plugin.Catalog {
 						Schema:  c.Type.Schema,
 						Name:    c.Type.Name,
 					},
-					Comment:  c.Comment,
-					NotNull:  c.IsNotNull,
-					Unsigned: c.IsUnsigned,
-					IsArray:  c.IsArray,
-					Length:   int32(l),
+					Comment:   c.Comment,
+					NotNull:   c.IsNotNull,
+					Unsigned:  c.IsUnsigned,
+					IsArray:   c.IsArray,
+					ArrayDims: int32(c.ArrayDims),
+					Length:    int32(l),
 					Table: &plugin.Identifier{
 						Catalog: t.Rel.Catalog,
 						Schema:  t.Rel.Schema,
@@ -252,6 +253,7 @@ func pluginQueryColumn(c *compiler.Column) *plugin.Column {
 		NotNull:      c.NotNull,
 		Unsigned:     c.Unsigned,
 		IsArray:      c.IsArray,
+		ArrayDims:    int32(c.ArrayDims),
 		Length:       int32(l),
 		IsNamedParam: c.IsNamedParam,
 		IsFuncCall:   c.IsFuncCall,

internal/codegen/golang/go_type.go

@@ -1,6 +1,8 @@
 package golang
 
 import (
+	"strings"
+
 	"github.com/sqlc-dev/sqlc/internal/codegen/sdk"
 	"github.com/sqlc-dev/sqlc/internal/plugin"
 )
@@ -48,9 +50,12 @@ func goType(req *plugin.CodeGenRequest, col *plugin.Column) string {
 		}
 	}
 	typ := goInnerType(req, col)
-	if col.IsArray || col.IsSqlcSlice {
+	if col.IsSqlcSlice {
 		return "[]" + typ
 	}
+	if col.IsArray {
+		return strings.Repeat("[]", int(col.ArrayDims)) + typ
+	}
 	return typ
 }
 

internal/compiler/output_columns.go

@@ -31,6 +31,7 @@ func (c *Compiler) OutputColumns(stmt ast.Node) ([]*catalog.Column, error) {
 			IsNotNull:  col.NotNull,
 			IsUnsigned: col.Unsigned,
 			IsArray:    col.IsArray,
+			ArrayDims:  col.ArrayDims,
 			Comment:    col.Comment,
 			Length:     col.Length,
 		})
@@ -289,6 +290,7 @@ func (c *Compiler) outputColumns(qc *QueryCatalog, node ast.Node) ([]*Column, er
 							NotNull:      c.NotNull,
 							Unsigned:     c.Unsigned,
 							IsArray:      c.IsArray,
+							ArrayDims:    c.ArrayDims,
 							Length:       c.Length,
 						})
 					}
@@ -626,6 +628,7 @@ func outputColumnRefs(res *ast.ResTarget, tables []*Table, node *ast.ColumnRef)
 					NotNull:      c.NotNull,
 					Unsigned:     c.Unsigned,
 					IsArray:      c.IsArray,
+					ArrayDims:    c.ArrayDims,
 					Length:       c.Length,
 					EmbedTable:   c.EmbedTable,
 					OriginalName: c.Name,

internal/compiler/query.go

@@ -21,6 +21,7 @@ type Column struct {
 	NotNull      bool
 	Unsigned     bool
 	IsArray      bool
+	ArrayDims    int
 	Comment      string
 	Length       *int
 	IsNamedParam bool

internal/compiler/query_catalog.go

@@ -52,14 +52,15 @@ func (comp *Compiler) buildQueryCatalog(c *catalog.Catalog, node ast.Node, embed
 
 func ConvertColumn(rel *ast.TableName, c *catalog.Column) *Column {
 	return &Column{
-		Table:    rel,
-		Name:     c.Name,
-		DataType: dataType(&c.Type),
-		NotNull:  c.IsNotNull,
-		Unsigned: c.IsUnsigned,
-		IsArray:  c.IsArray,
-		Type:     &c.Type,
-		Length:   c.Length,
+		Table:     rel,
+		Name:      c.Name,
+		DataType:  dataType(&c.Type),
+		NotNull:   c.IsNotNull,
+		Unsigned:  c.IsUnsigned,
+		IsArray:   c.IsArray,
+		ArrayDims: c.ArrayDims,
+		Type:      &c.Type,
+		Length:    c.Length,
 	}
 }
 

internal/compiler/resolve.go

@@ -218,6 +218,7 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 								NotNull:      p.NotNull(),
 								Unsigned:     c.IsUnsigned,
 								IsArray:      c.IsArray,
+								ArrayDims:    c.ArrayDims,
 								Length:       c.Length,
 								Table:        table,
 								IsNamedParam: isNamed,
@@ -283,6 +284,7 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 							NotNull:      p.NotNull(),
 							Unsigned:     c.IsUnsigned,
 							IsArray:      c.IsArray,
+							ArrayDims:    c.ArrayDims,
 							Table:        table,
 							IsNamedParam: isNamed,
 							IsSqlcSlice:  p.IsSqlcSlice(),
@@ -459,6 +461,7 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 						NotNull:      p.NotNull(),
 						Unsigned:     c.IsUnsigned,
 						IsArray:      c.IsArray,
+						ArrayDims:    c.ArrayDims,
 						Table:        &ast.TableName{Schema: schema, Name: rel},
 						Length:       c.Length,
 						IsNamedParam: isNamed,
@@ -569,6 +572,7 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 								NotNull:      c.IsNotNull,
 								Unsigned:     c.IsUnsigned,
 								IsArray:      c.IsArray,
+								ArrayDims:    c.ArrayDims,
 								Table:        table,
 								IsNamedParam: isNamed,
 								IsSqlcSlice:  p.IsSqlcSlice(),

internal/compiler/to_column.go

@@ -14,6 +14,13 @@ func isArray(n *ast.TypeName) bool {
 	return len(n.ArrayBounds.Items) > 0
 }
 
+func arrayDims(n *ast.TypeName) int {
+	if n == nil || n.ArrayBounds == nil {
+		return 0
+	}
+	return len(n.ArrayBounds.Items)
+}
+
 func toColumn(n *ast.TypeName) *Column {
 	if n == nil {
 		panic("can't build column for nil type name")
@@ -23,9 +30,10 @@ func toColumn(n *ast.TypeName) *Column {
 		panic("toColumn: " + err.Error())
 	}
 	return &Column{
-		Type:     typ,
-		DataType: strings.TrimPrefix(astutils.Join(n.Names, "."), "."),
-		NotNull:  true, // XXX: How do we know if this should be null?
-		IsArray:  isArray(n),
+		Type:      typ,
+		DataType:  strings.TrimPrefix(astutils.Join(n.Names, "."), "."),
+		NotNull:   true, // XXX: How do we know if this should be null?
+		IsArray:   isArray(n),
+		ArrayDims: arrayDims(n),
 	}
 }