The nine general partners of Village Apartments, a North Dakota general partnership, appeal from a judgment enforcing their personal guaranties of the partnership’s second mortgage debt with First Interstate Bank of Fargo, N.A. First Interstate cross-appeals from the denial of its motion to amend its complaint to seek recovery of losses from the resale of the mortgaged property. We overrule Mandan Security Bank v. Heinsohn, 320 N.W.2d 494 (N.D.1982), and hold that the anti-deficiency statutes apply to the general partners’ personal guaranties of a general partnership’s mortgage debt; however, we apply our decision prospectively. We therefore affirm the judgment.
On June 30, 1975, Gate City Savings and Loan Association loaned H & H Investment Company $260,000 to construct two apartment buildings in Wahpeton, North Dakota. The loan was secured by Short-Term Mortgage Redemption Act mortgages of $130,000 on each building. See NDCC Ch. 32-19.1. H & H later conveyed the two buildings to Village Apartments subject to the mortgages.
On April 30, 1982, First Interstate loaned Village Apartments $175,000. As security for the loan Village Apartments gave First Interstate a second mortgage on the two buildings. First Interstate and Village Apartments renewed the loan on January 31, 1983. On September 11, 1987, First Interstate and Village Apartments again renewed the loan and extended the mortgage. The loan renewal documents included a $90,000 unsecured promissory note, a $142,448.45 promissory note secured by the second mortgage, and continuing, unconditional guaranties of payment of the partnership’s debt by the partners. All the partners signed the loan renewal agreement, the promissory notes, and the personal guaranties.
Village Apartments defaulted on its loans with Gate City and with First Interstate, and Gate City sued Village Apartments to foreclose the 1975 mortgages. On October 18, 1988, foreclosure judgment was entered. At a sheriff’s foreclosure sale on December 15, 1988, Gate City bought the two buildings for the amount of the partnership’s debt with it and obtained Sheriff’s Certificates of Sale on Foreclosure for the two buildings.
On January 15, 1989, First Interstate sued the partners on their personal guaranties. The partners answered and, on two separate occasions, moved to amend their answer to assert that the anti-deficiency statutes precluded First Interstate from enforcing the guaranties without first foreclosing its second mortgage. The trial court denied the partners' motions, concluding that existing law did not support that claim.
On June 15, 1989, First Interstate purchased the Sheriff’s Certificates of Sale on Foreclosure from Gate City for $221,053.63 and in September 1989 sold the buildings for $197,044.54. First Interstate then moved to amend its complaint to seek recovery of $23,109.09, the difference between the price it paid Gate City and the price it received for the apartment buildings. The court denied First Interstate’s motion. The partners moved to dismiss First Interstate’s complaint, contending that, by taking the assignment from Gate City, First Interstate stood in Gate City’s shoes and because Gate City bought the apartment buildings for the amount of the partnership’s debt with it, First Interstate took the property in satisfaction of all mortgage indebtedness. The court denied the partners’ motion and subsequently ordered judgment for $162,741.42 against the partners, jointly and severally, as the balance due on their personal guaranties. The partners appealed, and First Interstate cross-appealed.
The partners argue that the anti-deficiency statutes preclude First Interstate from enforcing the guaranties without first foreclosing its second mortgage, and that the trial court abused its discretion in denying their motions to amend their answer to raise that claim. Their argument depends on the continued validity of Mandan Se*541curity Bank v. Heinsohn, 320 N.W.2d 494 (N.D.1982). Our analysis of their argument requires a brief description of the anti-deficiency statutes and their application to personal guaranties of mortgage debts.
The development, purpose, and history of the anti-deficiency statutes and the procedures for foreclosing real estate mortgages have been described in First State Bank of Cooperstown v. Ihringer, 217 N.W.2d 857 (N.D.1974). See also East Grand Forks Federal Savings & Loan Ass’n v. Mueller, 198 N.W.2d 124 (N.D.1972) [Teigen, J., dissenting]. NDCC Ch. 32-19 and 32-19.1 prescribe the procedures for foreclosing real estate mortgages and obtaining deficiency judgments.
Under the anti-deficiency statutes when a lender takes a mortgage on real property as security for a promissory note, the lender foregoes the right to proceed directly against the mortgagor on the note and instead receives the added protection of an interest in the property. Mischel v. Austin, 374 N.W.2d 599 (N.D.1985); H & F Hogs v. Huwe, 368 N.W.2d 553 (N.D.1985). The Legislature has prohibited deficiency judgments for real estate mortgages given under the Short-Term Mortgage Redemption Act. NDCC 32-19.1-07.1 For other real estate mortgages, NDCC 32-19-04, 32-19-06, and 32-19-07,2 direct that a court *542shall not render a deficiency judgment except under very limited circumstances in a separate action against the parties personally liable for that part of the debt, with recovery limited to the difference between the amount due and the fair value of the land.
In First State Bank of Cooperstown v. Ihringer, 217 N.W.2d 857 (N.D.1974), we considered the applicability of the anti-deficiency statutes to a non-mortgagor debtor. In Ihringer a husband and wife executed a note but only the husband executed the mortgage as security for the note. The mortgagee did not foreclose on the mortgage, but sued the wife on the note. Based on the language of NDCC 32-19-06, authorizing an action for a deficiency judgment “against the party or parties personally liable for that part of the debt,” we held that the anti-deficiency statutes applied to the non-mortgagor debtor and concluded that the mortgagee could:
(1) foreclose without asking for a deficiency judgment, or (2) foreclose, asking for a deficiency judgment in a separate action after the sale of the property, and obtain a judgment for only the difference between the mortgage debt plus costs and the fair value determined by a jury against both mortgagors and nonmortga-gors personally liable on the note, or (3) sue on the note without foreclosure but with recovery limited to the difference between the amount due on the note plus costs and the fair value of the property determined by a jury.
Ihringer, 217 N.W.2d at 864. Ihringer thus requires a mortgagee to comply with the anti-deficiency statutes when bringing an action against the parties personally liable for the debt.
In Bank of Kirkwood Plaza v. Mueller, 294 N.W.2d 640 (N.D.1980), we considered the interrelationship of personal guaranties of a mortgage debt of a corporation and the anti-deficiency statutes. There a bank and a corporation executed three promissory notes secured by real estate mortgages. Four individuals also personally guarantied payment of the corporation’s debt. When the corporation defaulted, the bank brought a foreclosure action against it and also independently sued the individual guarantors on their personal guaranties. We concluded that the anti-deficiency statutes did not apply to the independent action against the individual guarantors because those statutes did not clearly cover guarantors and because the action was based on a separate and distinct contract of guaranty and not on an obligation imposed by the notes or the mortgages.
Later, in Heinsohn, 320 N.W.2d 494, we applied a similar analysis to guaranties of a partnership mortgage debt by four partners. A majority of this court held that the anti-deficiency statutes did not preclude a mortgagee from recovering on the partners’ personal guaranties of a partnership’s *543mortgage debt. The majority concluded that the partners had changed the nature of their obligation on the partnership’s debt from joint liability as a partner to joint and several liability as a guarantor. Relying on Bank of Kirkwood Plaza, the majority held that the partners’ individual guaranties were valid, separate obligations to pay the partnership debt, and that recovery on the guaranties was not precluded by the anti-deficiency statutes because liability was predicated on the separate guaranties and not on the mortgage debt.
Here, the partners of Village Apartments argue that Heinsohn should be overruled. They assert that because a partnership is an association of persons and not a separate legal entity, they were already jointly liable for the partnership’s mortgage debt and their personal guaranties added nothing to their liability. They contend that the distinction made in Heinsohn, between partners’ joint liability for a partnership’s mortgage debt and partners’ joint and several liability on their personal guaranties, is inappropriate to allow circumvention of the anti-deficiency statutes. Relying on Hagan v. Havnvik, 421 N.W.2d 56 (N.D.1988), and First National Bank & Trust of Williston v. Ashton, 436 N.W.2d 215 (N.D.1989), the partners argue that because they were already liable for the partnership debt, their “guaranties” were not a “promise to answer for the debt, default, or miscarriage of another person” under NDCC 22-01-01(1) and that the anti-deficiency statutes are applicable.
In Hagan, a vendee on a contract for deed also executed a personal guaranty of performance of the contract for deed. When the vendee defaulted, the vendor sued to foreclose the contract for deed and also sought to enforce the personal guaranty. Because the vendee was both the principal debtor and the guarantor of the contract for deed, we ruled that the vendee’s guaranty was not separately enforceable because it was not “a promise to answer for the debt, default, or miscarriage of another person” under NDCC 22-01-01(1). We thus concluded that the anti-deficiency statutes applicable to the vendor’s action precluded a deficiency judgment in the foreclosure action.
In Ashton, three individuals executed a promissory note secured by a mortgage and simultaneously executed personal guaranties of the mortgage debt. Upon default, the mortgagee sued the individuals on their personal guaranties. We applied the rationale from Hagan, and concluded that the individuals had not executed “guaranties” under NDCC 22-01-01(1) because the signors were both principal debtors and guarantors. We concluded that the individuals were already jointly and severally liable for the debt pursuant to the promissory note and that the “guaranty” did not enlarge their obligation.3 We thus held that the anti-deficiency statutes were applicable.
Using the same analysis as in Hagan and Ashton to analyze the nature of a partner’s liability for a partnership debt, we now conclude that the distinction we relied upon in Heinsohn is inappropriate to preclude application of the anti-deficiency statutes to a general partner’s personal guaranty of a general partnership’s mortgage debt.
A partnership is an association of persons. NDCC 45-05-05(1). For service of process, a partnership is not a legal entity, separate and distinct from its members. 501 DeMers, Inc. v. Fink, 148 N.W.2d 820 (N.D.1967). Although any partner may enter into a separate obligation to perform a partnership debt, partners are jointly, not severally, liable for the debts and obligations of the partnership. NDCC 45-06-07(2). However, under a contract of guaranty, the guarantors’ liability is both joint and several. Heinsohn was based on this distinction between those two types of liability. The distinction is illusory-
*544In a “joint liability,” the joint obligors have the right to insist that they be joined as co-defendants and sued together. Williams v. Reed, 113 Cal.App.2d 195, 248 P.2d 147 (1952); Schram v. Perkins, 38 F.Supp. 404 (E.D.Mich.1941); Black’s Law Dictionary, p. 838 (6th ed. 1991). In a “joint and several liability,” each co-obli-gor, individually, has the duty of performing the obligation, and the obligee can sue all or any one of them separately. Swint v. Fountain, 106 Ga.App. 509, 127 S.E.2d 381 (1962); Schram v. Perkins; Black’s Law Dictionary, p. 837 (6th ed. 1991). Thus the distinction between “joint” and “joint and several” liability is said to be the separate obligation of obligors in joint and several liability that is not present in joint liability alone.
North Dakota statutes blur this distinction. Whenever suit is brought against defendants jointly indebted, a creditor may proceed against the defendant served and if the creditor receives a favorable judgment “it may be entered against all the defendants thus jointly indebted to the extent only that it may be enforced against the joint property of all and the separate property of the defendants served.” NDCC 32-30-01(1); Continental Supply Co. v. Syndicate Trust Co., 52 N.D. 209, 202 N.W. 404 (1924). This statute goes on to say that “[wjhere all the defendants have been served, judgment may be taken against any of them severally, when the plaintiff would be entitled to judgment against any one or more of such defendants if the action had been against such defendants or any of them alone.” NDCC 32-30-01(3). Thus, when all the parties jointly liable on an obligation are sued together, there is no real distinction between “joint” and “joint and several” liability.4 We believe that this procedural trifle is inappropriate to override the Legislature’s recognized public policy controlling deficiency judgments in real estate litigation. See Borsheim v. Owan, 467 N.W.2d 95 (N.D.1991); Brunsoman v. Scarlett, 465 N.W.2d 162 (N.D.1991); First State Bank of New Rockford v. Anderson, 452 N.W.2d 90 (N.D.1990). Substantively, a partner’s guaranty of a partnership debt is not a separate obligation.
General partners who personally guaranty a general partnership’s mortgage debt have not changed the nature of their obligation on the debt.5 The partners are parties personally liable for the partnership’s debt [see First State Bank of Cooperstown v. Ihringer, 217 N.W.2d 857] and, pursuant to NDCC 22-01-01(1), the partners have not personally guarantied the debt of another. First National Bank & Trust of Williston v. Ashton, 436 N.W.2d 215; Hagan v. Havnvik, 421 N.W.2d 56. Compare Bank of Kirkwood Plaza v. Mueller, 294 N.W.2d 640.6 We therefore conclude that when general partners personally guaranty a general partnership mortgage debt, the anti-deficiency statutes are applicable, and that the procedures for deficiency judgments outlined in First State Bank of Cooperstown v. Ihringer must be satisfied.
First Interstate nevertheless contends that, because of its contractual expectations, our decision must be applied prospectively. We agree.
In Forster v. North Dakota Workers Compensation Bureau, 447 N.W.2d 501, *545504 (N.D.1989), we considered a similar question:
In Olson v. Dillerud, 226 N.W.2d 363 (N.D.1975), this court noted a number of relevant considerations to be used in determining whether or not a court decision should be given prospective effect, and quoted from the United States Supreme Court opinion in Chevron Oil Co. v. Huson, 404 U.S. 97, 92 S.Ct. 349, 30 L.Ed.2d 296 (1971), as follows:
“In our cases dealing with the nonre-troactivity question, we have generally considered three separate factors. First, the decision to be applied nonret-roactively must establish a new principle of law, either by overruling clear past precedent on which litigants may have relied, ... or by deciding an issue of first impression whose resolution was not clearly foreshadowed, ... Second, it has been stressed that ‘we must ... weigh the merits and demerits in each case by looking to the prior history of the rule in question, its purpose and effect, and whether retrospective operation will further or retard its operation.’ ... Finally, we have weighted the inequity imposed by retroactive application, for ‘[w]here a decision of this Court could produce substantial inequitable results if applied retroactively, there is ample basis in our cases for avoiding the “injustice or hardship” by a holding of nonretroactivity.’ ” Dillerud, 226 N.W.2d at 369.
See also Metropolitan Life Insurance Co. v. Commissioner of Department of Insurance, 373 N.W.2d 399 (N.D.1985). Compare James B. Beam Distilling Co. v. Georgia, — U.S. -, 111 S.Ct. 2439, 115 L.Ed.2d 481 (1991). Applying those factors to this case, we conclude that our decision should be given prospective effect.
Our decision overrules clear past precedent upon which lenders have relied to structure their contractual relations. The law in effect when a contract is made becomes part of the contract. Lillethun v. Tri-County Electric Cooperative, Inc., 152 N.W.2d 147 (N.D. 1967). The rights and obligations of contracting parties cannot be altered by subsequent legislation or judicial decision. State v. Klein, 63 N.D. 514, 249 N.W. 118 (1933). See also First Federal Savings & Loan Association v. Haley, 357 N.W.2d 492 (N.D.1984). In 1987 First Interstate and Village Apartments restructured their loan agreement to include the partners’ personal guaranties of the partnership’s mortgage debt. The law in Heinsohn became part of their contractual relationship. It would violate the parties’ contractual obligations and expectations to retroactively apply our decision overruling clear past precedent. We conclude that our decision applies prospectively and therefore does not apply to these guaranties. Accordingly, we conclude that the trial court did not err in denying the partners’ motions to amend their answer to raise the anti-deficiency statutes.
First Interstate argues that the trial court erred in denying its motion to amend its complaint to permit recovery of the $23,-109.09 loss it suffered on the resale of the apartments. The partners counter that the trial court erred in denying their motion to dismiss First Interstate’s action because First Interstate took the property from Gate City in satisfaction of the partnership’s debt with First Interstate.
When First Interstate purchased the Sheriff’s Certificates from Gate City, it obtained Gate City’s mortgage interest in the apartments. See First National Bank of Minot v. MacDonald Construction Co., 137 N.W.2d 667 (N.D.1965). Although the partners are liable to First Interstate on their guaranties with First Interstate, the partners did not personally guaranty their mortgage debt with Gate City. First Interstate stepped into the shoes of Gate City for the partnership’s debt with Gate City. Gate City’s mortgage is governed by the Short-Term Mortgage Redemption Act which directs that “the mortgagee or any party claiming by, through, or under said mortgagee shall not be entitled to any judgment for deficiency.” NDCC 32-19.1-07. [Emphasis added]. Here, First Interstate took the property “by, through, or under” Gate City. Allowing First Interstate to also recover the losses it incurred when it sold the apartments would be al*546lowing a deficiency judgment. We conclude that the trial court did not err in denying First Interstate’s motion to amend its complaint. Because the partners are liable on their personal guaranties of the partnership’s debt with First Interstate, we also conclude that the trial court did not err in denying the partners’ motion to dismiss First Interstate’s action.
The district court judgment is affirmed.
VANDE WALLE and GIERKE, JJ., concur. PEDERSON, Surrogate Judge, sitting in place of LEVINE, J., disqualified.. NDCC 32-19.1-01 defines the scope of the Short-Term Mortgage Redemption Act and says:
Mortgage may provide for foreclosure under chapter. The parties to a real estate mortgage upon property involving an area not to exceed forty acres [64.76 hectares] may provide in said mortgage that upon default in the conditions of the mortgage the mortgage may be foreclosed as provided in this chapter.
NDCC 32-19.1-07 says:
No deficiency judgment allowed. — When any mortgage has been foreclosed under this chapter, the mortgagee or any party claiming by, through, or under said mortgagee shall not be entitled to any judgment for deficiency.
. NDCC 32-19-07 says, in part:
Other suits prohibited.
******
Except as otherwise provided in sections 32-19-04 and 32-19-06, neither before nor after the rendition of a judgment for the foreclosure of a real estate mortgage ... shall the mortgagee ... be authorized or permitted to bring any action in any court in this state for the recovery of any part of the debt secured by the mortgage ... foreclosed. It is the intent of this section that no deficiency judgment shall be rendered upon any note, mortgage, or contract given after July 1, 1951, to secure the payment of money loaned upon real estate or to secure the purchase price of real estate, and in case of default the holder of a real estate mortgage ... shall be entitled only to a foreclosure of the mortgage ... except as provided by sections 32-19-04 and 32-19-06.
NDCC 32-19-04 says:
What complaint shall state. — In an action for the foreclosure or satisfaction of a mortgage, the complaint shall state whether any proceedings have been had at law or otherwise for the recovery of the debt secured by such mortgage, or any part thereof, and if there have been, whether any and what part thereof has been collected. The plaintiff shall also state in his complaint whether he will in a later and separate action demand judgment for any deficiency which may remain due to him after sale of the mortgaged premises against every party who is personally liable for the debt secured by the mortgage.
NDCC 32-19-06 says, in part:
What judgment must contain — Deficiency judgments and other suits prohibited in excess of amount by which debt exceeds fair value of mortgaged premises — Determination of fair value of mortgaged real property.
******
The court may not render a deficiency judgment for any sum whatever against the mortgagor or purchaser, or the successor in interest of either, except as hereinafter provided. Where a note or other obligation and a mortgage upon real property have been given to secure a debt contracted after July 1, 1951, and the sale of the mortgaged premises has failed to satisfy in full the sum adjudged to be due and the costs of the action, the plaintiff may, in a separate action, ask for a deficiency judgment, if the plaintiff has so indicated in the complaint, against the party or parties personally liable for that part of the debt and costs of the action remaining unsatisfied after the sale of the mortgaged premises. The separate action for a deficiency judgment must be brought within ninety days after the sale of the mortgaged premises. The court, in the separate action, may render a deficiency judgment against the party or parties personally liable, but the deficiency judgment may not be in excess of the amount by which the sum adjudged to be due and the costs of the action exceed the fair value of the mortgaged premises. In case the mortgaged premises sell for less than the amount due and to become due on the mortgaged debt and costs of sale, there is no presumption that the premises sold for *542their fair value. In all actions brought for a deficiency judgment and before any judgment can be rendered therein, the determination of the fair value of the mortgaged premises must first be submitted to a jury at a regular term or to a jury impaneled for that purpose, and no deficiency judgment may be rendered against the party or parties personally liable unless the fair value of the mortgaged premises is determined by the jury to be less than the sum adjudged to be due and the costs of the action.... At that time and place the party or parties may offer evidence to show the fair value of the mortgaged premises even though they may not have otherwise appeared in the action for a deficiency judgment. Any deficiency judgment obtained must be enforced by execution as provided by law, except that no execution may be enforced after three years from the date of the rendition of the deficiency judgment. The mortgagee or vendor or the successor in interest of either is not permitted or authorized either before or after the rendition of a judgment for the foreclosure of a real estate mortgage or the cancellation or the foreclosure of a land contract, if the mortgage or contract was made after July 1, 1951, to bring any action in any court in this state for the recovery of any part of the debt secured by the mortgage or contract so foreclosed or canceled in excess of the amount by which the debt and the costs of the action exceed the fair value of the mortgaged premises. The fair value must be determined by a jury in the same manner as the fair value is determined in cases where a deficiency judgment is sought in an action to foreclose the mortgage and such judgment must be enforced by execution as provided by law except that the execution may not be enforced after three years after the date of the rendition of the judgment.
. NDCC 22-01-12 says:
Limitations upon obligation of guarantor.— The obligation of a guarantor must be neither larger in amount, nor in other respects more burdensome, than that of the principal. If in its terms the obligation exceeds that of the principal, the obligation is reducible in proportion to the principal obligation.
. NDCC 9-01-08 also says:
“Joint obligation — Contribution. A party to a joint obligation or to a joint and several obligation who satisfies more than his share of the claim against all obligors may require a proportionate contribution from all the parties joined with him."
. This conclusion is buttressed by the requirement of NDCC 22-01-12 that the obligation of a guarantor cannot be more burdensome than that of the principal. In this context, if the difference between "joint” and “joint and several” liability creates a separate and distinct obligation, then a partners’ obligation is made more burdensome in contravention of NDCC 22-01-12 whenever a general partner individually guaranties a general partnership’s mortgage debt.
.Because a corporation is a separate entity, our decision in Bank of Kirkwood Plaza remains unchanged. Moreover, our decision does not apply to limited partners’ individual guaranties of a limited partnership’s mortgage debt because limited partners are not liable for the obligations of a limited partnership. NDCC 45-10.1-22.